TRANSACTIONS OF SECTION C. 



611 



The metamorpliisai of the series by granitic intrusions is briefly referred to 

 and the age of the various groups discussed. 



Taking into account the evidence from the dififerent areas, the author concludes 

 that the Highland rocks are the oldest, and are of Archjean age. 



The Jasper and Green Rock Series though newer are most probably of prfe- 

 Cambrian age, and not Arenig, as the author formerly supposed. These views 

 agree in the main with those put forward by Mr. Kinahan, to whom the credit of 

 establishing the prae-Cambrian age of these Green Rocks is primarily due. 



4. The Fossil Flora of the Cumherland Coalfield. 

 By E. A. Newell Arber, M.A., F.G.S. 



The Cumberland coalfield lies along the coast-line to the west of the 

 mountains of the Lake District. The towns of Whitehaven, AVorkington, and 

 Maryport are three of the most important centres of the coal industry in Cumber- 

 land. In this district the Upper Carboniferous rocks consist of two series, of 

 ■which the upper is the well-known * Whitehaven Sandstone.' This is essentially 

 an arenaceous deposit, and is often red or purple in colour. It is generally 

 believed to lie unconformably on the ' Coal Measures ' below, the latter consisting 

 of argillaceous and carbonaceous material, and containing almost all the workable 

 coals. 



The horizons of both the ' Whitehaven Sandstone ' and the ' Coal Measures ' in 

 the Carboniferous are disputed questions. Recently some attempt has been made 

 to throw fresh light on the subject, from the evidence of the plant-remains which 

 occur in both series, although not so abundantly as in some other coalfields. A 

 full account of the floras, and the conclusions which have been attained, will, it is 

 hoped, be published shortly elsewhere. 



5. The Post-Glacial Deposits of the Belfast District. 

 By R. Lloyd Praeger. 



The silted-up head of Belfast Lough and other similar places in the district 

 display a remarkably fine series of deposits extending from the close of the Glacial 

 epoch to the present day, with a rich fauna, from which much of the history of 

 the intervening period may be gleaned. A typical section at Belfast shows the 

 following sequence : — 



Blue I 



Surface clays . 

 Yellow sand . 



clav I ^PP®^ 

 •^ \ Lower 



Grey sand 



Peat 



Grey sand 



Eed sand 



Boulder clay (base not reached) 



45 



The peat bed, which at Belfast is 20 feet below low- water level, reappears 

 between tides at various other places in the district. It represents an old land 

 surface, and its fossils include the ' Irish Elk.' The blue clay is the most im- 

 portant bed of the series. Two divisions can be clearly distinguished in it, the 

 lower clay being littoral, and characterised by such shells as Scrohicularia 

 piperata, the upper yielding an abundant fauna pertaining to five to ten fathoms 

 of water ; Thracia convexa is a characteristic fossil. In both clays some of the 

 bivalves occur in beds, each shell in its natural position, and many of the species 

 attain remarkably large proportions. In places the Scrohicularia clay is overlaid 



BR 2 



