﻿CONCLUSION. 



Streptorhynchus giyas, M'Coy. PI. XVI, figs. 2, 



— umbraeulum, vel crenistria. Some fragments apparently attributable to tliis shell. 



— vel Leptcena sp. ? PI. XVIII, figs. 13, 14. 

 Orfhis (vel Lept(cna) laticosta, Conrad. 



— hipparioni/x, Vanuxein ? Large internal casts. PI. XVII, figs. S — 12. 



The following geological details have been kindly furnished me by Mr. Pcngclly : 

 '■ East and AVest Looe, in Cornwall, arc two small towns on the oppositcs sides, and 

 at the month, of the narrow tidal estuary of the River Looe, and are situated about fourteen 

 miles, nearly due west, from Plymouth. The rocks of the district arc essentially bluish 

 grey slates ; the stratification is beautifully distinct, and the dip, both in amount and 

 direction, is characterised by very considerable uniformity, through great vertical and 

 horizontal spaces. 



"According to Prof. Sedgwick it is about thirty degrees east of true south, at an angle 

 of forty degrees (' Quarterly Journ., Geol. Soc./ vol. viii, p. 16). In some places there is a 

 considerable amount of interstratified schistose grit, and a few thin calcareous bands here 

 and there present themselves. What appears to be contemporary hornblendic ash is 

 occasionally met with, and in some localities quartz-veins are numerous. Some of the less 

 gritty beds are not unfrequently ferruginous, in which case the newly exposed surfaces are 

 of a yellowish -brown or reddish-brown colour ; these are the principal, but by no means the 

 only, repositories of organic remains. All the Looe Brachiopoda (described in this 

 Monograph) were from beds of this character. 



" Well-defined joints, most of them at (sensibly) right angles to the plane of the 

 horizon, and also to that of stratification, are common, and such as have been some 

 time exposed to the weather, frequently disclose small orifices, which are trustworthy indi- 

 cations of fossils. 



" The remarkable Coral Pleurodictyum jiroblematicum, which, according to Murchison, is 

 a characteristic fossil of the Lower Devonian rocks (Table, p. 433, ' Siluria,' 2nd ed., 1S59), 

 is very abundant in the same beds. Some of the specimens are of considerable dimensions, 

 measuring fully seven inches in diameter. This Coral occurs also in the slates of 

 Meadfoot, Torquay. Mr. Godwin-Austen speaks of it as ranging through the whole 

 middle slate-district of South Devon ('Trans. Geol. Soc.,' 2nd series, vol. vi, part 2, 

 page 408). 



" The finer varieties of the Looe slates contain the fossils formerly known as the 

 ' Polperro Fish-remains,' but which have been pronounced to be Sponges by Messrs. 

 M'Coy and Carter, who founded the genus Steganodicii/um for their reception. These 

 Sponges extend from Looe, westward as far as Fowey, and eastward to the Kame Head, 

 at the entrance of Plymouth Sound. I have met with them also at Bedruthen Steps, on 

 the north coast of Cornwall, a few miles south of Padstow Harbour ; and at Mudstone 

 Bay, near Brixham in South Devon, in the slates which underlie the great limestones of 

 Berry Head and Sharkham Point. Like Pleuroc/idyum, they are confined to slate-rocks." 



