172 GEOLOGICAL HISTORY. 



Lonsdale, we should have had an instructive group of laminated 

 Upper Ludlow rocks, and tilestones, with plenty of small littoral 

 shells, Spongariae, Aviculae, Cypricardiae, Orthocerata, &c. Such 

 forms of life very probably existed over the sea-bed within the 

 area which we are considering; they may have been imbedded 

 in Upper Silurian strata, and have been raised from their place 

 even to constitute land, but if so, they have been wasted away 

 and removed by a process soon to be traced. The fishes of this 

 period, so far as we know them, were very small*, and belong to 

 the upper strata of the series. 



PTERICHTHYAN PERIOD. No monuments of this period re- 

 main in Yorkshire, unless the sandstone beds, which I have de- 

 scribed elsewhere f beneath the limestone of Moughton Fell in 

 Eibblesdale, should be referred to it. But in the neighbouring 

 valley of the Lune at Kirkby Lonsdale, we have the coloured 

 marls and massive conglomerates which accompany the Old Red 

 Sandstone series, the characteristic strata of this period round 

 the English lakes and the Lammermuir hills, well exhibited. 



When we proceed farther north and reach the Grampians and 

 the great Caledonian valley, the Red Sandstone yields a con- 

 siderable number of the strange fishes known as Pterichthys, 

 Cephalaspis, Coccosteus, &c., which have furnished to Mr. Miller 

 the theme of a pleasing and instructive volume J. Mantell has 

 recently described a reptile (Telerpeton Elginense) from these 

 strata, and eggs of Batrachians are supposed to have been dis- 

 covered in them. But though no monuments of the period, 

 strictly so called, rocks or fossils, can be 'traced, there are 

 some marks for its history in Yorkshire; for previous to it the 

 older strata were uplifted by some great subterranean force, cer- 

 tain main features of our physical geography were sketched out, 

 and it is probable that land was above the waves in a consider- 

 able part of what is now Cumbria, Scotland, and Ireland. One 



* Murchison's ' Silurian System.' 



t Illustrations of the Geology of Yorkshire, Part II. 



J ' The Old Red Sandstone.'' 



