On the Augitic Rocks of the Canary Islands. 569 



12. "The Submerged Forest of Barnstaple Bay." By Towns- 

 hend M. Hall, Esq., E.G.S. 



IB. " On a Section of Boulder-clay and Gravels at Ballygalley 

 Head. By T. Mellard Beade, Esq., C.E., E.G.S. \ 



The section described is in a gravel-pit about 30 feet deep, situa- 

 ted between Larne and Cushendall, in the north of Ireland. It shows 

 a considerable thickness of false-bedded gravel and sand, containing 

 shells, covered by Boulder-clay. The shells collected from the 

 sand and gravel of this section do not, however, agree with those 

 found in the so-called " Interglacial beds " of Lancashire ; and the 

 author regards the section as confirming his views that the tripartite 

 division of the drift-deposits is not, as maintained by Hull and other 

 geologists, equally applicable to the Irish and Lancashire deposits. 



14. " On the Augitic Bocks of the Canary Islands." By Prof. 

 Salvador Calderon. Communicated by the President. 



As the result of a long investigation of the eruptive rocks of the 

 Canaries, and especially of Las Palmas, the author has come to the 

 conclusion that there are two groups of such rocks in those islands 

 — an older one, characterized by the presence of hornblende, and a 

 newer, containing augite. In the latter he finds the essential 

 minerals to be plagioclase, augite, magnetite, olivine, sanidine, and 

 nepheline ; and he distinguishes among them the following kinds of 

 rocks, all of which have their characteristic minerals imbedded in a 

 paste of augite and plagioclase : — 1. Augite- andesite, with a small 

 quantity of sanidine; 2. Tephrine, with no sanidine, but abundance 

 of nepheline ; 3. Basanite, with some peridote ; 4. Nepheline-basalt 

 with abundance of peridote ; 5. Dolerite, crystalline, characterized 

 by the disappearance of nepheline, the abundance of peridote and 

 porphyritically imbedded plagioclase, augite, and olivine ; 6. Felspa- 

 ihie basalt (like 5, but semicrystalline) ; and 7. Essentially olivinic 

 modern lavas. 



15. " On the Cambrian (Sedgw.) and Silurian Beds of the Dee 

 Valley, as compared with those of the Lake-district." By J. E. 

 Marr, Esq., B.A., E.G.S. 



The principal differences in these districts appear to be due, 



(1) to the non-correspondence of the epoch of volcanic activity, 



(2) to the upheaval and consequent denudation of a part of North 

 Wales after the end of the Cambrian period. The author correlates 

 the deposits in the two areas, the Dee valley having deposits parallel 

 to the various members in the Lake-district, from the Skiddaw 

 Slates to the Upper Coldwellbeds inclusive. The Lower Bala series 

 contains ash-beds which appear to be andesite. In the Middle 

 Bala of Wales are some fossils which, in the Lake-district, occur in 

 the Ashgill Shales above the Coniston Limestone. He finds the 

 equivalents of the Graptolitic Mudstone of the Lake-district, near 

 Carrig-y-druidion, correspondent in stratigraphical position, litho- 

 logical character, and fossils. One Graptolite, G. colonus, however, 

 occurs at a higher horizon in the Lake -district. In the lowest 

 division of the Denbigh Grits Acroculia haliotis is found, which, in the 

 Lake-district, occurs in the Upper Coldwell beds ; and in the upper- 



Phil. Mag. S. 5. No. 52. Suppl Vol. 8. 2 Q 



