A HISTORY OF WARWICKSHIRE 



Wilmcote they were excellently exposed in quarries as described by 

 Wright ; the White Lias consisting of hard crystalline limestone, below 

 which follow marls and blackish shales with Estheria minuta and the 

 characteristic Avicula contorta and Pecten -valoniensis. A bone bed has 

 been noted at Temple Grafton. Strickland recorded the presence of 

 black shales and yellow sandstone at Bidford, and Brodie 1 has given 

 details of the sections exposed on the Stratford and Fenny Compton 

 railway. The railway section of the Rhstics and Lower Lias at Har- 

 bury, south-east of Leamington, has long been famous ; the yellow 

 sandstone with Estheria minuta is present below the White Lias. Still 

 farther along the base of the Lias the Rhastic beds have been exposed 

 on the London and North- Western railway west of Church Lawford 

 near Rugby ; according to Mr. Woodward 2 they consist of 5 or 6 feet 

 of buff limestones overlying 5 to 8 feet of greenish-grey marl ; the 

 Avicula contorta shales appear to be unrepresented. 



Brodie 3 described two interesting outliers or small isolated patches 

 of Lower Lias and Rhastic beds south-west of Henley-in-Arden, and 

 another, still farther away from the main tract, at Knowle. The Rha;tic 

 beds of these outliers have yielded some of the usual characteristic fos- 

 sils. The Knowle outlier which is situated some 10 miles to the north 

 of the main Liassic tract is interesting as showing the former extension 

 of these beds in a northerly direction ; Dr. Lloyd of Leamington seems 

 to have been the first to detect its existence. The Lias limestones were 

 formerly wrought by shafts. The Rhstic shales contain a band of yellow 

 micaceous sandstone with the fossil bivalve Pullastra arenico/a, and were 

 noted by Brodie as exposed in the banks of the canal. 



From the foregoing details of the Warwickshire Rhaetic beds it 

 would appear that they do not present anything like the full develop- 

 ment as exhibited in the classic sections of Penarth or Aust on the shores 

 of the Bristol Channel ; as Mr. Woodward * points out, ' there is a 

 development of sandy beds, the black shales are very thin in places, and 

 near Church Lawford they are absent; again, the White Lias north of 

 Harbury is somewhat sandy, it shows current-bedding and ripple-marks, 

 and is itself occasionally nodular,' and he concludes that the beds of our 

 district were laid down not far from a local margin of the deposit. By 

 the end of the Keuper Marl period the general subsidence of the whole 

 British area which had been going on from the close of the Bunter 

 epoch had resulted in the submergence of the barriers which had 

 hitherto kept out the sea; this now gained access to our district, 

 and with it the period of the desert and lacustrine Red Rocks came 

 to an end; and henceforward marine deposits alone were laid down 

 over the site of the future Warwickshire. As we have seen, the first 

 of these consists of the Rhatic limestones and shales which serve merely 

 as an introduction to the Lias. 



' Quart. Journ. Gtol. Soc. XH. (1874), 746. Op. cit. p. 162. 



Quart. -Journ. Geol. Soc. xxi. (1865), 159. < Op. cit. p. 151. 



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