OTHER CLYDE ISLANDS. 351 



probably due to the action of the sea upon the sandstone 

 during the progress of the last elevation of the land. 



A very interesting shelly deposit here has been described 

 by Rev. H. W. Crosskey and Mr. D. Robertson. It is 

 situated near Millport, on a terrace 32 feet 9 inches above 

 sea level, and 200 yards from the shore, near the resi- 

 dence of the Hon. Mr. Boyle. The section gives (order 

 descending) 



Earth Mould, . . . 1| feet. 



Gravel, 4 ,, 



Shell-bearing Sand, . . 14 ,, (not pierced through). 



There were collected forty-four species of shells, one of 

 polyzoa, four Crustacea, two echinoderniata, and seventeen 

 of foraminifera. The character of the shells places it among 

 the glacial beds. For a detailed list, see Tr. Geol. Soc. GL, 

 vol. iii. p. 116. A remarkable circumstance about the 

 deposit is its sandy character, only ten ounces of clay in 

 seven and a-half pounds of the deposit. It resembles in 

 this respect the croffcamic bed on the Forth and Clyde 

 Junction Railway, (see Jour. Geol. Soc.) The gravel con- 

 tained fragments of trap (local), quartz (local), and schist 

 (travelled). 



LITTLE CUMBRAE. 



152. The Lesser Cumbrae is about two miles long and one 

 mile broad, and in its bolder outlines strongly contrasts with 

 the sister isle; its highest point has an elevation of about 

 800 feet. In geological structure and in altitude it cor- 

 responds with the southern division of Bute; and, like the 

 Garrochhead district of that island, consists wholly of trap 

 sandstone only appearing in one spot on the east shore, 

 near the old keep. This patch, however, is sufficient to 

 shew that the foundation of the island is made of the same 

 sandstone which forms the Great Cumbrae and the ad- 

 joining mainland. Piled up over the sandstone foundation 



