378 spencer: the yoredale and millstone grit rocks. 
place down to Hebden Bridge Railway Station and the deep 
dales of the Hebden and Horse Bridge Clough have also been 
excavated out of the same rocks. 
In the Withins valley, divided from that of Todmorden by 
a narrow ridge of Kinder, the Yoredale shales are also exposed. 
The Yoredale shales of the Hebden and Horse Bridge Clough 
valleys have long been famous for the rich suites of beautiful 
fossils which they have yielded to fossil collectors. 
One or two layers of disconnected blocks of impure lime- 
stone of varying sizes occur in the shales of these valleys ; the 
upper portions of many of them contain abundance of marine 
remains such as Goniatites, Nautilus, Orthoceras, Aviculopecten, 
Posidonomya, Buccinum, fish-remains, &c. Occasionally drifted 
fragments of Dadoxylon and other vegetable remains are found in 
them. In each of these valleys there are also several outcrops of 
beds of shale, containing crushed Goniatites, Aviculopecten, and 
other marine fossils. There is at least one bed containing the 
remains of a small species of encrinites, of which not only frag- 
ments of the stems but also nearly complete specimens with heads 
have been found. In the limestone blocks such undoubted 
Mountain Limestone fossils as Productus, Spirifera, Belerophon, 
Pleurotomaria, Pecten, Natica, Modiola, Goniatites, Nautilus, 
Orthoceras, encrinites, &c., (fee, occur. 
The Yoredale shales, taken as a whole, are of marine origin, 
as shown by their marine remains, but here and there we have 
indications of ancient land surfaces, such as coal beds, seat 
earths, and galliard rocks full of stigmarian roots and plant- 
remains. 
Upon one of my visits to Horse Bridge Clough a number of 
-men were busy at work digging out foundations for a weir, and 
had exposed a face of about three yards in depth and five or six 
yards across the bed of the stream. When I turned to examine 
the material brought out I found, to my surprise, that it was 
Jiterally full of plant remains in a great variety of species. 
