486 G. H. KmaJian — Water Basin of Lough Derg. 



35 mm. ; breadth, 16 mm. ; greatest breadth of carapace, 65 mm. ; 

 length along dorsal line, 55 mm. ; from front border to tip of lateral 

 spine, 65 mm. 



Locality. — Kirktonholm Cement Works, E. Kilbride, in shale over 

 the Calderwood Cement Stone; Lower Carboniferous L-imestone 

 Group. Collected by Mr. J. Bennie. 



{To he continued.) 



EXPLANATION OF PLATE XVL 



[All the figures on this Flate are of the natural size."] 



EiG. \. — Bithyrocaris testudinea, Scouler. Carboniferous Limestone series, east of 



Paisley. 

 Fig. 2. — Bithyrocaris tricornis, Scouler. Carboniferous Limestone Series near 

 Glasgow. 

 In this specimen the eaudal segment (c) and tail-spines have been displaced, 



and are seen protruding from the latero-anterior border of the carapace. 

 The two maxillse are plainly to be discerned at {g) ; they agree in form 

 precisely with those already figured and described by H. Woodward (see 

 ■Geol. Mag., 1865, Vol. II. p. 401, Plate XL); they have also been 

 figured in Portlock's Geological Eeport on Londonderry (pi. xii. fig. 6). 

 . The carapace in this specimen has been folded together, the under portion 

 ■protruding from the anterior end at («), the median spine of the posterior 

 border is seen at {p), and the two spines marking the latero^posterior 

 angles are thus brought closely together. 

 Figs. 1 and 2 are drawn from Dr. IScouler's original type specimens, lent 

 to H. Woodward for examination by the Trustees of the Andersonian 

 Museum, Glasgow. 

 Fig. 3. — A nearly perfect carapace of B. tricornis, lying spread out upon the matrix, 

 so as to display the normal outline of the shield ; the caudal segments (c) 

 are detached, but lie near to the posterior border {p). Lower Carbon- 

 iferous series, East Kilbride. Coll. Geo!. Survey Scotland, Edinburgh. 



R 



III. — ^The Water Basin op Lough Derg, Ireland. 



By G. Henry Kinahan, M.R.I. A., etc. 



(PLATE XVII.) 



OME time since, I read before the Geological Society of Glasgow 

 \^ a paper on " The Valley of Loch Lomond," and pointed out 

 that the deeps and shallows corresponded with the faults and breaks 

 in the adjoining country. This paper was quoted by His Grace the 

 Duke of Argyll, President of the London Geological Society, in 

 opposition to the view (so ably advocated by Professor Ramsay) that 

 ice has been the principal, if not the only, agent engaged in the 

 formation of such hollows. 



It was suggested that my observations in this case may have been 

 hastily made ; but the valley of Loch Lomond is not the only water 

 basin that I have examined with the help of the Admiralty Charts. 

 I have carefully contoured the chart of Loch Fyne, also in Scotland ; 

 while in Ireland I have contoured those of Loughs Mask, Corrib 

 and Derg ; also the chart of the fjord called Killery Harbour, Cos. 

 Galway and Mayo, with those of Cork Harbour, and of the archi- 

 pelago between Crookhaven and Eoaring-water Bay, Co. Cork. In 

 all of these I find a remarkable coincidence between the lines of 

 faults or breaks and the deep soundings ; while ni}' colleague, E. T. 

 Hardman, F.R.G.S.I., finds a similar connexion between the faults 

 and deeps in the basin of Lough Neagh, and Mr. John Ball, F.E.S., 



