184 PROF. T. T. GROOM ON THE GEOLOGICAL [Feb. 1900, 



either rests conformably upon the Coal Measures, and overlaps them 

 at certain points ; or else it lies unconformably upon, and oversteps 

 them in places. If the hypothesis of overlap were true, it might 

 be expected that no new Permian beds could appear elsewhere 

 between the Breccia and Coal Measures; but, so far from theTrappoid 

 Breccia remaining at the base of the Permian system, lower horizons 

 appear as the beds are traced away from the Abberley district 

 towards the north and north-east. 



Thus at Warshill, according to Mr. Wickham King, the Trappoid 

 Breccia no longer rests directly upon Coal Measures, or older rocks, 

 as in Woodbury and Abberley Hills, but on some 70 feet of Middle 

 Permian marls and sandstones, themselves underlain by Lower 

 Permian marls. 1 In the Enville district a considerable thickness 

 of sandstones, conglomerates, and marls underlies the Breccia 2 : 

 the Middle Permian beds alone, as defined by Mr. King, increasing 

 in thickness from 200 to 330 feet when traced towards the north- 

 western part of the area. 3 In the Clent Hills a thickness of over 

 500 feet of sandstones, conglomerates, and marls intervenes between 

 the Trappoid Breccia and the Upper Coal Measures. At West 

 Bromwich 700 feet of red sandstones and marls overlie the Upper 

 Coal Measures ; at San dwell Park 575 feet of sandstones and marls, 

 and at Hamstead 1353 feet of similar rocks occupy the same 

 horizon. 4 



There is, moreover, some positive evidence of unconformity 

 between the ' Permian ' and Upper Coal Measures. For though 

 Mr. Cantrill regards the Wyre Forest Permians as 'Coal-Measure 

 Passage-Beds,' 5 and considers that in some places there is con- 

 formity between them and the Upper Coal Measures, he remarks 

 that in other places there appears to be a certain amount of break, 

 as, for instance, in the neighbourhood of the Trimpley anticline. 6 

 It would appear also from the Geological Survey map, and parti- 

 cularly from that given by Mr. D. Jones, 7 that the Permian near 

 Bridgenorth transgresses across the Upper Coal Measures so as to 

 rest upon their basal beds. 



It would seem fairly certain, then, that the Haffield Breccia 

 or Trappoid Breccia of the Western Midlands rests unconformably, 

 not only upon the Archaean, Silurian, Old Red Sandstone, and older 

 Coal Measures, but also upon the Upper Coal Measures, where these 

 are present. When the last-named are absent, this circumstance is 

 due, in part at least, to denudation. Pre-Permian denudation in 



1 Quart. Journ. Geol. Soc. vol. lv (1899) pp. 110 & 111. I see no reason 

 to doubt, as Mr. Kins: has done in his paper (p. 101), the identity of the Trap- 

 poid Breccia of the Malvern and Abberley Hills with that seen at Warshill and 

 other areas north of the Abberley district. 



2 E. Hull, 'Trias & Permian of Midlands' Mem. Geol. Surv. 1869, p. 12. 

 » Quart. Journ. Geol. Soc. vol. lv (1899) table facing p. 108. 



4 T. C. Cantrill, Quart. Journ. Geol. Soc. vol. li (1895) pp. 530-532. 



5 Unci. p. 547. 



t! Bid. p. 542, and ' Geol. of Wyre Forest Coalfield ' Kidderminster, 1895, 

 pp. 34 & 36. 



7 Trans. Fed. Inst. Min. Eng. vol. vii (1894) pi. xiv. 



