296 PEOCEEDiNGS OF THE GEOLOGICAL SOCIETY. [March 25, 



Fig. 2. Eurypterus scorpioides, Salter, MS. (ventral aspect), two-fifths the 

 natural size, a, a. Basal joints of antemiee. b, b. Spinous palpi, m. Me- 

 tastoma or postoral plate, e, e. Ectognaths, or swimming-feet. t. Part 

 of thoracic plate. Original specimen in Museum of Practical Creology, 

 Jermyn Street. 



Fig. 3a, Supposed brancliial plates of Fterygotus bilobus, var. crassus, H.Woodw. 

 Natural size. 



Fig. 3 b. A single leaflet of the plates, drawn from a larger detached specimen. 

 Original specimens in the British Museum. All from the Uppermost Silu- 

 rian, Lanarkshire. 



2. On the Conistoi^ Group. By Professor R. Haekness, F.E.S., 

 F.G.S., and H. A. E"iciioLso]>f, D.Sc, M.B., F.G.S. 



The * Quarterly Journal of the Geological Society ' for 1865-66 

 (vol. xxii. p. 480) contains a memoir by the authors, entitled " Ad- 

 ditional Observations on the Geology of the Lake-Country." In this 

 memoir, after alluding to some new fossils from the Skiddaw- Slate 

 group, and the occurrence of a fossiliferous ash-bed in the green 

 slates and the porphyries in the Lake-country proper, the existence 

 of several faults among the old rocks of this portion of England is 

 indicated, and the total absence of strata containing characteristic 

 Upper-Llandovery and Wenlock fossils is pointed out. The Kendal 

 flags, the highest member of the Silurian series in the Lake-dis- 

 trict, were also referred to as showing no distinct connexion with 

 the older rocks lying to the north of them ; and it was stated that 

 these Kendal flags are probably brought against the older members 

 of the Silurian rocks by means of faults. 



The object of the present communication is to point out the occur- 

 rence in the Lake-country of a new and unique horizon containing a 

 rich Graptolite fauna in that portion of the Silurian series which has 

 been termed by Prof. Sedgwick " the Coniston Flags," to describe 

 in detail these flags, to point out their relations, both physi- 

 cally and palseontologically, with the Coniston limestone below 

 them and the Coniston grits above them, and by this means to add 

 a great thickness of strata to the highest member of the Lower Silu- 

 rian rocks as this member is represented in the British isles. 



The range of the Coniston limestone, the base of the series of 

 rocks to which this communication refers, was described many 

 years ago by Prof. Sedgwick, and also its position*. 



This limestone, in its furthest extension in the eastern portion of 

 the Lake -district, is seen at Shap Wells, being here immediately 

 covered up by Old Red Sandstone on its eastern side. Westward 

 from Shap Wells, for about two miles, the country is low and moory, 

 and no further trace of this band of limestone is seen until Scale 

 Head, a farmhouse a little south-west of AVastdale Crag, is reached. 

 Here, in the course of a small brook, we have the limestone again 

 appearing, but in a very diff'erent condition from that which it exhibits 

 at all the other places where it can be recognized. At this spot it 

 occurs in the form of a white semicrystalline limestone, having 

 imbedded within it imperfect crystals of orthoclase, the form of 

 * Trans. Geol. Soc. 2nd series, vol. iv. p. 47 et seq. 



