9^ HEPORT— 1876. 



The total depth attained up to this time ia 2035 feet. The boring commences 



n the Lower Lias at a spot about 6 miles south-west of the city of Lincoln, and 



after traA-ersing the Lias, Rhsetic, Keuper, and Bunter beds, the Upper Permian 



and Lower Permian, it entered the Carboniferous formation at a depth of 1901 feet, 



the remainder of the section being in Carboniferous strata. 



The general succession is as follows : — 



Depth. Thickness. 

 ft. ft. 



AlluTium " . 10 10 



Lower Lias Clay 60 50 



RhfeticBeds? .,.;»-•.?■■''■'"'■■■• 1^^? ^5? 



-p- ( Marls ■.:;■. v.: '/;:.-;•;-;;'. . 706 sgi 



*^^»¥^^ ] Lower Sandstone • '••'ii4'- • ^^® ^*^^ 



Bunter Sandstone !?'.'.'."*.'. . 1500 542 



-p . j Upper Marls and Magnesian Limestone 1884 384 



1 ermian j Lower Sandstone 1900 1(5 



f Grey grits with plants ; shales with 



j small bivalves {Anthracoda) 1955 55 



Carboniferous J Bluish calcareous shales and earthy 



Beds 1 limestone ....-„..-. ... ,,. 2030 65 



I Fine breccia ■•;'.■. '.\ ;■;.•.. .', 2024 4 



[Chocolate-coloured hard clays 2030 6 



The temperature at 2000 feet was 79° F., taken with one of Negretti's thermo- 

 meters supplied by Professor Everett, of Belfast. At a depth of 917 feet a strong' 

 feeder of water was encountered in the Lower Keuper Sandstone, and a still stronger 

 at 12-50 in the Bunter Sandstone, when the water rose 4 feet above the ground. 

 This water uncjuestionably percolates underground from a distance of 10 or 12 

 miles, where the beds crop out. 



This boring is exceedingly interesting as giving the depth of the Carboniferous 

 rocks so far from the borders of the Nottinghamshire coal-field, and as giving the 

 thickness of the overlying formations ; but it has (unfortunately for the spii-ited 

 gentlemen who have undertaken it) not as yet produced any satisfactory results. 

 The Carboniferous beds are of so peculiar a character that I hesitate to attempt to 

 identify them with any particular division of the Carboniferous system. Mean- 

 while, as the boring is still being prosecuted, it is hoped that specimens of a more 

 definite nature may be brought up. 



On Tertiary Basalt-rock Dykes in Scotland. By E. L. Jack, F.G.S. 



On some New Minerals, and on Doubly -refracting Garnets. 

 By Dr. Von Lasatjlx. 



The writer exhibited specimens of the new mineral which he terms melnnophla- 

 gite, in consequence of its peculiaiity of becoming black when heated before the 

 bloAvpipe. It occurs in very small cubic crystals, of pale brown colour, seated on 

 little scalenohedra of calcite, which are associated with the sulphm- and celestine 

 of Girgenti, in Sicily. According to analyses, melanophlagite contains 815-29 per 

 cent, of silica, 7'2 of sulphuric acid, or some acid of the thionic series not yet de- 

 termined, 2'8 of strontia, 2-86 of water, and small quantities of alumina and ferric 

 oxide. Dr. Von Lasaulx also exhibited specimens of his new species aerinite, and 

 several microscopic sections of garnets which exhibited double refraction. He 

 entered into an explanation of the causes of such optical irregularities in monometric 

 crystals, and referred them partly to the effects of tension, partly to chemical altera- 

 tion, and partly to complexity of structure, due to alternations of isotropic and 

 anisotropic minerals. Thus the variety of garnet called colophonite appears to be a 

 mixtm-e of true garnet and idocrase ; hence, whilst one part exhibits single refrac- 

 tion, another part shows double refraction. 



