EXCURSION XV. 185 



the Pecten Islandicus, and Astarte borealis the only two 

 absolutely arctic. By far the greater number of shells 

 are in single valves or in a broken state, yet not 

 so small but that the species can be determined. This 

 fragmentary condition of the shells shews a very disturbed 

 state of the waters along the coast on which they lived. 

 But even on stormy sea-coasts, with stony shore, sandy 

 mud, and broken shells, there are sheltered places inside of 

 points, and behind banks and ledges of rock; and there can 

 be no doubt that, somewhere about here, if one could 

 happily alight upon it, there must be some such bed of 

 unbroken shells indicating a quiet deposit. 



The following section gives the succession of beds at this 

 place in ascending order : 



1. Boulder-clay, twelve to twenty feet thick. 



2. Clay-bed with shells, seven to ten feet. 



3. Dark sandy bed with open texture, four or five feet 

 apparently local. 



4. An upper drift of sand and stones; thickness variable. 



5. A compact bed of stones, with less sand, forming a 

 marked line on the cliff, but not easily reached; thickness 

 five or six feet. 



6. An upper drift, similar to No. 4. 



7. Surface soil. 



These upper drifts, covered in front with their facing, or 

 wash, look very like the boulder-clay; but a closer examina- 

 tion, and removal of the false face, shew them to be very 

 different. They are much less compact, more loose and 

 easily broken, generally more sandy; and the stones are 

 mostly angular, or, if polished, the surface has a finish very 

 inferior to that of the stones in the boulder-clay; as if 

 they had been exposed, since the polish was put on, to 

 some continued wearing action. In fact, they have very 

 much the appearance of a river deposit; and in looking 

 at some of the heaps of detritus left by floods on the sides 

 of the stream below, it struck us how very like they were 



