The Geology Of The Highlands, &C.

THE GEOLOGY OF THE HIGHLANDS , & c .

Sir , —Under the above title an article of mine appeared in your paper of 30 th September , 1861 , giving an outline of a Neptunian system of geology , differing in many respects from all others . By this theory it is assumed that our globe was gradually condensed irom nebular matter ; the irregular outline of hills and valleys being the effects of ani rregular flow of the ocean at the period

that the different geological formations were being deposited ; the stratified rocks being deposited in flowing waters ( some of them being chemical , others the waste of previous formations ) , whilst the unstratified , or those rooks that have been erroneously ascribed to submarine volcanic actions , were precipitated in the crystalline form , in spaces of quiet waters , and wers brought to

a state of rest , by various modes of opposing flows meeting and balancing each other , and the type , or external form of such unstratified rocks are determined by the form under which the opposing flow meet . As the origin of the unstratified rooks is the cardinal point betwixt the Plutonian geologist and myself , the point that will prove the truth of the system propounded

by Dr . Hutton , or the Neptunian system propounded by me , I beg you will be so kind as to permit me , through the medium of your journal , to state more clearly than in my former letter , the origin of the unstratified rocks . In my former letter I gave examples of four modes by which four distinct types of unstratified rocks were formed ; each type differing in structure and external form from the others . On this occasion I will confine

myself to two examples that are generally well known , viz ., Edinburgh Castle rock aud Dumbarton Castle rock , which differ from each other in external form and structure . Let me here premise that the above-named rocks were formed contemporaneously with the carboniferous formations , ancl that tho ocean's level was higher than those formations , the nebular or elementary matter having

not yet chemically combined , consequently , the volume of the semi-fluid , and gaseous ocean , was greater than at a subsequent period , the higher parts of the primary regions were alone above the ocean ' s level , the lower hills being a mass of breakers during this period , from the lateral pressure of the ocean on the west side of the Grampians ; side currents were forced east through and

the valleys ^ and passes ofthe G-rampians . The currents from the Forth , Yenacher , & c , conjoined , flowing eastward , betwixt the Touch hills , on the S , W ., and the Ochils on the N . E . of Stirling , carrying down the waste of the highlands , and cutting its way through the westward flow of the ocean . In the conflict betwixt the easterly flow of the current , and the westerly flovy of the ocean , in many parts we may presume that the opposing flows balanced each other , and that spaces of water were

brought to a state of rest betwixt them , and where the opposing flows balanced each other , the matter in solution was precipitated in the crystalline form , in the whole space of quiet water , and as the spaces of quiet water would have different shapes according to the forms that opposing flows balanced each other ; thence the difference in external form of tho unstratified rocks .

The site of Edinburgh Castle rock , being one of the places where the ocean current , flowing down the track of the valley of the Forth , and the westerly flow ofthe ocean , balanced each other , and brought a space of water betwixt the flows to a state of vest , in . this space of quiet water the unstratified rock of the castle was gradually precipitated in the crystalline form , and thus the crystalline

foundation was laid ; the sea in its slower westerly flow , deposited the sand against it , drifting easterly from the crystalline rock , whilst the more rapid flow of the current from the west , deposited no sand on the west side , but rushed past the crystalline deposit with redoubled force , preventing the deposition of sand in its track : thence the origin of the north Loch , now Princes-street Gardens , and the Cowgate of Edinburgh . Achemical head indurated the mass , where the sandstone and crystalline rock were

The Geology Of The Highlands, &C.

m contact , and electro-chemical action , consequent upon the contact of dissimilar surfaces , changed both to a harder and msre brittle condition at tbe junction than they were at a distance . I will now briefly give the second example . Contemporaneously with the above , a ' current flowed west from the primary hills of the South East of Scotland , filling

the whole valley of the Clyde ; at the same time another current flowed south , by Loch Lomond , filling the whole valley of the Severn , and flowing directly into the side of the superior ocean current of the Clyde . The inevitable consequence of such a conflict was a recoil in the weaker current of the Severn , so as to bring a space of water to a state of rest in the centre of the Severn

current , a short distance behind the point of contact , betwixt the opposing currents ; further , the shape of the water at rest would likely have a triangular shape , such is the shape of Dumbarton rock . In this space of quiet water Dumbarton rock was precipitated in the crystaline form , the current flowing past ,, on each side of the quiet water , but too rapid to permit the deposition of

sand , thence the isolation of Dumbarton rock . Had the Severn current , instead of flowing directly into the side of the Clyde , flowed south-west , so as to enter the Clyde slanting , no such phenomena as Dumbarton rock would have existed . I do not ask any one to adopt the above views , further than they are warranted by facts , but it is folly to meet them with the opinions of eminent men , whose arguments in favour of the volcanic origin of the above class of rocks , " I have examined and found wanting . The only rational

way of combating me , is by bringing forward geological facts at variance with the theory I have propounded . For instance , the type of unstratified rocks like the Castle rock of Edinburgh can only be formed in , and beside valleys that have their outlets from primary regions eastward , such as in the valley of the Forth . It is impossible upon my theory such type could be formed in valleys whose

outlet from the primary regions is westward , such as in the valley of the Clyde ; because , in this instance , the current flowing west , and the ocean flowing west , of course there could be no such conflict between opposing flows , in the valley of tbe Clyde as in the valley of Forth . Now , if a type can be produced in the valley of the Clyde like the castle rock of Edinburgh , I will at once confess

my theory to be unsound , or if a reason can be given why similar types could not be erupted in valleys having a westerly outlet to those that were erupted in valleys having an easterly outlet , let that reason be given . Again , if a type like Dumbarton rock can be shown , excepting where two valleys or two rivers meet , such as in the instance of the Clyde aud the Severn , I at once confess my

theory to be untenable ; further there is a remarkable type of unstratified rock at Drummond Castle , near Crieff , that differs in external form and structure from both the above types . Now it is impossible upon my theory , that a type like that near Gruff , could be formed in either the valleys of the Forth or Clyde , but if my opponents can produce one instance of a similar type iu any of the above-named valleys , I at once retire from all geological contests . JAMES DRUMJIOND . Grief , February , 1863 .

A Night In The Catacombs Of The Nile.

A NIGHT IN THE CATACOMBS OF THE NILE .

No feature in the mental idiosyncracy of the Egyptians is so striking as their passion for excavating , burrowing , and building under ground . Half the lives of the thoughtful classes of the community , who were so numerous and influential as to impress their peculiarities on the whole nation , was passed in subterraneous apartments , nominallconstructed for the reception of the dead but

y , in reality , for the use of the living , who loved the grini silence and solitude which the company of mummies ana the perpetual presence of death insured to the frequenters of the tombs . Accordingly there is scarcely a mountain )