640 . J.J. H, TEALL ON THE CHEMICAL AND 
44, On the Curmicat and MicroscopicaL Cuaractrers of the WHIN 
Sint. By J.J. H. Teas, M.A., F.G.S. (Read June 25, 1884.) 
[Prats XXIX.] 
LITERATURE. 
Wincn, N. J. On the Geology of Northumberland and Durham. Trans. 
Geol. Soe. vol. iv. p. 73. 1817. 
Forster, Westcarty. Section of Strata, &c. 2nd edit. p. 111. 1821. 
Trevetyan, W. C. Sketch of the Geognosy of Part of the Coast of Northum- 
berland. Mem. Wernerian Soe. vol. iv. part ii. p. 253. 1822. 
Sepewick, ApAmM. On the Association of Trap Rocks with the Mountain 
Limestone Formation of High Teesdale. Cambr. Phil. Trans. vol. ii. 
p. 139. 1827. 
Forster, Francis. On the Geology of Ratcheugh Crag, near Alnwick. Trans. 
Nat. Hist. Soc. North. vol. i. p. 75. 1831. 
Trevetyan, W.C. Notice of a Bed of Whin at Stanhope in Weardale. Trans. 
Nat. Hist. Soc. North. vol. i. p. 58. 1831. 
Woop, N. On the Geology of Northumberland. ‘Trans, Nat. Hist. Soe. 
North. vol. i. p. 308. 1831. 
Puitiirs, Joun. Geology of Yorkshire, part ii. p. 85. 1836. 
Horron, Wituiam. On the Stratiforim Basalt associated with the Carboniferous — 
Formation of the North of England. Trans. Nat. Hist. Soc. North. 
vol. 11. p. 187 (1838); also in Proe. Geol. Soc. vol. i. p. 341. 
Boyp, E. F. Ona part of the Carboniferous or Mountain Limestone Series of 
Northumberland. Trans. North of England Inst. of Engineering, vol. ix. 
p: 18. 18612 
Tate, GrorcE. The Geology of the District traversed by the Roman Wall. — 
Appendix to ‘The Roman Wall, by Dr. J. Collingwood Bruce; 3rd 
edit. 1867. 
History of Alnwick, p. 469. 1869. Also papers in Proc. Ber. Field- 
Ciub and Trans. Tyneside Nat. Hist. Field-Club. 
Auuport, G. On the Microscopic Structure and Composition of British Car- 
boniferous Dolerites. Q.J.G.S. vol. xxx. p. 552. 1874. 
Croven, C. Tf. The Section at High Force, Teesdale. Q.J.G.8. vol. xxxii. 
Piceo. LST G. 
——. The Whin Sill of Teesdale as an assimilator of the surrounding Beds *. 
Geol. Mag. decade 2, vol. vii. p. 433. 1880. 
* This paper contains the following two analyses of the rock of the Wkin 
Sill, made in Dr. Percy’s Laboratory, which I quote for comparison with my 
own, given in the body of the present paper :— 
I TT, 
Siok eee ee 51-47 50:35 
ATO toh MEN Ne A 16°48 16°80 
Recs Macrae eons 3-61 3-51 
eos eS ; 849 8:36 
io 0-46 0-41 
CHO ee eee 8-22 9-01 
MeO." eed. 5°10 5°73 
Ouse. seem ai 3-28 2:87 
ree em 1:18 1-07 
hee eee Le tg 08 
H.On ener” 1°70 2-00 
100-16 100°19 
CD: ee ke te 782 284 
I, From Tinkler’s Syke, top of Widdy Bank Fell. 
If. From Teward’s Bridge, near Forest Church. TiO, was not estimated 
