498 John Smith — The Great Submergence. 



deducting 62 feet for the superficial deposits the thickness is 

 454 feet, being about double the amount it was expected to be. 

 There was an abrupt change from the Red Marl into the underlying 

 Keuper Sandstone, which was penetrated to the depth of 244 feet, 

 when a fault was crossed and the Upper Soft Sandstone of the 

 Bunter proved to the depth of 13o feet. 



The Geological Survey Map of the district (Sheet 79, N.E.) dis- 

 tinguishes the Red Marl from the " Waterstones " at the base over 

 the centre of Wirral, but it does not seem possible to have made 

 such a distinction in South- West Lancashire, where both are included 

 iu the Red Marl. At Ford most of the marl is of an arenaceous 

 character, while on the east of Liverpool the beds are softer and 

 include more shale and clay. It seems, however, that the Keuper 

 Sandstone in Wirral is of less thickness than it is under Liverpool, 

 and that the upper beds there are represented by the " Waterstones." 



IX. — The Great Submergence : an Interpretation of the 



Clava Section, near Inverness, Scotland. 1 



By John Smith, Monkredding. 



fnHE interesting section at Clava, near Inverness, was first 



| examined geologically by Mr. James Fraser, C.E. ; and his 



remarks on it were published in the Transactions of the Geological 



Society of Edinburgh, vol. iv, part 2, and in the Transactions of 



the Inverness Field Club, vol. ii. 



As this section contains a thick bed of shelly clay situated at 

 a height of 508^- feet above sea-level, it has become, owing to its 

 uniqueness 2 in Scotland, of the very greatest interest to geologists, 

 so much so that it has been examined and reported on by a 

 committee appointed for the purpose. The finding of the majority 

 of the committee has been that the shelly clay is in position, as it 

 was deposited on a sea-bottom. The minority (Mr. D. Bell and 

 Mr. P. F. Kendall) think that the shells were carried uphill by ice 

 from Loch Ness, then an arm of the sea. I throw in my lot with 

 the majority, and shall give my reasons for doing so. 



At the invitation of Mr. Bell I had an opportunity of examining 

 the section, and spent part of a day there when the Committee 

 made one of their visits to Clava. This was at the time when 

 the large pit was dug, and there was an excellent opportunity of 

 inspecting the section, and especially the shelly clay. 



The section at the main pit, as published by the Committee, is as 

 follows, the lower part having been ascertained by boring : — 



Feet. 



1. Surf ace-soil and sandy boulder-clay 43 



2. Fine sand (stratified, yellowish-brown) 20 



3. Shelly blue clay with stones in lower part 16 



4. Coarse gravel and sand IS 



5. Brown clay and stones 21£ 



Solid rock, Old Bed grit. 



1 Read to the Geological Society of Glasgow, February 13, 1896. 



2 Since this was written I have discovered iu Ayrshire very numerous 

 exposures of shelly clay at various levels, from a little above high-water mark 

 to 1061 feet above sea-level. 



