390 W. H. Hiidlesfon — First Impressions of Assynt. 



A. Salteri in memory of my late fellow-worker in the Paleeozoic 

 Crustacea, Mr. J. W. Salter, F.G.S., for so many years PalEeontolo- 

 gist to the Geological Survey of Grreat Britain. 



Formation. — Upper Silurian (Wenlock Shale). 



Locality. — Pencarreg (or " Penkerrig"), Caemarthenshire. 



EXPLANATION OF PLATE IX. 



Figs. 1 — 7. Cardiocaris Hwmeri, H. Woodw., sp. nov. 



„ 8 — 12. veneris, H. Woodw., sp. nov. 



,, 13. lata, H. Woodw., sp. nov. 



„ 14 & 15. bipartita, H. Woodw.,, sp. nov. 



,, 16. Pholadocaris Leeii, H. Woodw., sp. nov. 



,, 1 — 16 from the Upper Devonian, Biideslieim, Eifel, Ehenish Prussia. 

 ,, 17. Aptychopais Salteri, H. Woodw, sp. nov. Upper Silm'ian (Wenlock 

 Limestone), Pencarreg, Caermarthensbire, S. Wales. 



All the specimens are figured of the natural size, and are from the Museum of 

 Mr. John Edward Lee, F.S.A., F.G.S., Villa Syracusa, Torquay. 



II. — FiKST Impressions of Assynt. 



By Wilfrid H. Htjdleston, M.A., F.G.S. ; 



President of the Geologists' Association. 



IT must be admitted that first impressions are to a certain extent 

 instinctive, and need not, therefore, be taken for more than they 

 are worth. To do any really valuable work in such a troubled dis- 

 trict as Assynt would require a considerable length of time. Still, 

 after having been nearly a fortnight in the place — a fortnight in 

 which the rainy days and the dry ones were about equally balanced 

 — it is almost impossible to avoid forming some idea as to the 

 respective merits of the interpretations which have been put forth. 

 And this one is all the more apt to do in order to be able to institute 

 comparisons with other districts of the North-West already visited 

 in previous years. 



Furnished with Professor Heddle's excellent geological map of 

 Sutherland (Mineralogical Magazine, No. 21), and furthermore 

 enjoying the society and experiences of the Professor himself, I 

 arrived, on the last day of July, in the wild and remote corrie which 

 flanks the north side of Ben More, having walked that morning from 

 the head of Loch Shin over peaty moors which for the most part 

 hide all the rocks. 



After wading across the upper Cassley between Fionn Loch More 

 and Fionn Loch Beg, and after toiling through a maze of glacial 

 debris and peat hags, we struck the solid rock at perhaps 1400 feet 

 above the level of the sea. From this point it is easy to perceive 

 that the east slope of Ben More is covered with quartzite, but I was 

 surprised to find that the bulk of the rocks in the corrie, which lies 

 beneath the northern slopes of Ben More and Coniveall, consists of 

 a peculiar gneissic rock which Dr. Heddle terms the " Logan " rock. 

 Some portions of this " Logan " rock are very puzzling, more 

 especially in its relations to a dark green or dull black aphanitic 

 rock which Dr. Heddle at one time was disposed to regard as igneous. 

 Continuing to ascend towards the Bealloch between Coniveall and 



