76 MODERN OEOLCGICAL CHANGES. 



members of the Secondary System^ with their terrible reptiles, realizing the 

 leviathan of Job; and the Tertiary Formations, with their mammoth quadrupeds, 

 in reading the mere description of which we are forcibly reminded of the 

 behemoth of the same sacred writer. 



It is not my intention, however, to dwell upon the ancient aspects of 

 natm*e. There are a series of changes which have taken place at a period 

 far enough remote according to man's limited chronology, but at a time, the 

 date of which, as compared with that of any of the epochs I have already 

 mentioned, may be emphatically said to be only ^'^of yesterday." It is some 

 of these I would now attempt to describe. My attention was more specially 

 directed lately to the modern changes of surflice on the Frith of Clyde, by 

 the following circumstance: — Visiting my friend Dr. Lorrain one evening, he 

 put into my hand a large and brilliant specimen of Trochus zizrphanus. The 

 shell is quite a common one, and I remarked it was so. ^'Ah ! but whei*e 

 was that one found, think you," said he; "nine feet below the surface, in 

 Sauchie-hall-Street \" And so it was. In digging a drain there, the workmen, 

 after going down about four feet, came to a bed of pure peat, one foot 

 thick, and below that they dug four feet through beds of stratified sand, 

 containing shells. Mr. James Petus, a patient of Dr. I^orrain's, who was close 

 beside the spot when they were found, attracted by the brilliancy of one, 

 the outer coat of which had scaled off, preserved it, remarking "It would 

 do for his doctor," He informed me that *a good many more were seen, but 

 no one thought them worth preserving. In one shovelful of sand thrown out, 

 there were as many as five or six. We have thus here a portion of a 

 deposit shewing that the sea, or at least an arm of it, at one time covered 

 the spot now occupied by the upper level of Sauchie-hall-Street, 



There are many other proofs of the same fact, some of which I will now 

 detail, confining myself to those found on the Frith of Clyde. Commencing 

 with the Island of Arran, we notice that the road from Brodick to Corrie, 

 and so on round the north end of the island, occupies a flat and level, but 

 not broad, space of ground, a little elevated above the level of the sea, and 

 backed by a series of cliffs of considerable height, and the vertical faces of 

 which are water- worn, and hollowed out into caves. The cliffs are of Sandstone, 

 and the caves are due to the action of waves at one time beating against 

 them. I visited the place, and obtained from the sides of a ditch, in what 

 was then a field waving with corn, many specimens of shells. They are 

 broken and worn; but when it is remembered that they were found at some 

 distance from the sea, and at a much higher level than the sea ever reaches 

 now, they are not without interest. In my note-book I find the following 

 account of my finding these shells: — I looked for the ancient beach all 

 along, but could not find a single shell. When we had passed Port-na-Claoch, 

 and were still a mile or so north of Markland Point, I asked an old man 

 who was working on the road whether he had ever seen any, as now, from 

 the profuse vegetation, I could sec none. He said he had often dug marl 



