34 POST-TERTIARY ENTOMOSTRACA. 



same as that which we have ah-eady described as underlying the clay more abundantly 

 charged with the arctic fauna of the district, although itself containing evidence of its 

 marine origin. The Boulder Clay can be traced to points at which it evidently passes 

 under the whole series of laminated and fossiliferous clays. 



At another point of the Hill two distinct fossiliferous beds can be traced, and the 

 series runs : 



1. Surface soil. 



2. Littoral shell-bed a few inches (with Littorina litorea,L. rudis, Mytilus edulis, &c., 

 all recent species). 



3. Clay with arctic species ; chiefly confined to a band of two to three feet. 



4. Laminated clay. 



A similar littoral shell-bed (2) is met with on the low ground on the north of Paisley, 

 about fifty feet lower than Jordan Hill. 



The two tidal belts represented by these littoral shell-beds could not have been 

 coexistent. 



Another curious feature in this deposit is the position of the Mussel-bed. While 

 Mytilus edulis certainly abounds in the youngest littoral beds, it is also found at greater 

 depths and overlain by arctic shells. 



At Paisley it is found twelve feet below the surface, at Muirhouse nineteen feet, at 

 Stobcross twenty-four feet, and at Jordan Hill fourteen feet. 



Mussel-beds undoubtedly existed, therefore, in the early periods of the deposition of 

 the arctic clays as well as in the most recent, indicating several changes of level in the 

 sea-bottom, and marking in the various heights at which they occur changes of elevation 

 in the land-surface. 



Height above the sea, sixty-three feet. 



The following Ostracoda were found 



Cythere pellucida, Baird. 



— castanea, G. O. Sars. 



— defiexa, nov. sp. 



— viridis, Miiller. 



— lutea, Miiller. 



— villosa (G. 0. Sars). 



— pulchella, Brady. 



