L. Richardnon — Rhcetic Section at Wigston. 369 



inches below this limestone-bed that I would draw the line between the 

 Lower and Upper Rhsetic, thus making the Upper Rhsetic the yellowish 

 and practically unfossiliferous portion and the Lower Rhsetic the 

 darker and distinctly fossiliferous portion. 



"Wilson and Quilter drew it at 2 feet below the most prominent 

 limestone-bed in the section, that is, below bed 9 ; but Montagu Browne 

 would take that bed, his bed G, as the " break between the Upper and 

 Lower Rhaetic, which appears ", he says, " rather to be determined by 

 the thick band of limestone (G) than by shales that ' pass down ' into 

 similar ones" (p. 36). 



At an earlier page (p. 32), however, Mr. Montagu Browne writes : 

 " The dark shales following above this basal bone-bed are those known 

 as the Lower Rhaetic 'Black Shales', ' Paper Shales', in whole or in 

 part, or Avicida-contorta-^hQle?, (D), and are generally carried as far 

 as the second band of limestone (G). In this instance I would prefer 

 to limit them, if not just under the first band of limestone (E), to not 

 far above thathorizon, on both lithological and paleeontological grounds." 

 So apparently he did not form any very definite idea as to where the 

 line should come. 



As Wilson and Quilter remark, the feature of the Pteria-contorta- 

 Shales that at once strikes anyone familiar with the Rhaetic of the 

 South-West of England is the rarity of hard bands. In the 29 feet 

 9 inches of deposit assigned to the Lower Rhsetic there are only two 

 noticeable hard bands, both limestones. The lower one is a line 

 of well-spaced septariform nodules, more widely separated than 

 Mr. Montagu Browne's diagrammatic section would lead one to infer. 

 The upper and principal band, however, is more continuous, being 

 made up of blocks of septariform limestone less commonly nodular. 

 This bed much reminds one of a similar limestone numbered 9 at 

 Langport and at several other Somerset sections. 



There is not so great a variety of Rhsetic fossils as might be 

 expected in these beds, but along certain lines such species as do occur 

 are individually very numerous, and fish — more perfect than is often 

 the case — are not uncommon at from 3 ft. 6 in. to 3 ft. 9 in. above 

 the base of the shales. A single ray of Ophiolepis Damesi has been 

 found, but not m situ. This is unfortunate, for its detection in situ 

 would have materially contributed towards the more accurate correlation 

 of the component beds of this section with their equivalents elsewhere, 

 seeing that it probably marks out a niveau at some 2 or 3 feet below 

 the Lower Pedcn-'Bedi. 



The queried record of Estheria minuta in bed E of Mr. Montagu 

 Browne's section, and the apparently certain record from his bed G, 

 require confirmation. Neither limestone looks to me at all like those 

 in which one would expect to find this phyllopod, and Mr. A. R. 

 Horwood — who kindly made a special search at my request — also 

 failed to detect any specimens. I should rather anticipate their 

 discovery in the marls and associated beds of the portion that I have 

 identified as Upper Rhaetic. 



It is obvious from the details that have been recorded by Mr. Montagu 

 Browne that these beds are subject to considerable variation, and that, 

 as I have also observed, the marls distinguished as a (Lower Lias) are 



DECADE V. VOL. VI. — NO. VIII. 24 



