clxx INFERIOR OOLITE AMMONITES. 



from those of the Cotteswolds : they are apparently earlier biogenetically, if not 

 geologically. Of course all this additional material has yielded many new forms ; 

 but only a few of the more conspicuous and important of them can be dealt 

 with now. 



I. Genus — Tmetoceras, S. Buckman. 

 1892. Tmetoceras, This Mouogr., p. 269. 



Remarks. — Species of this easily recognised genus mark, with one exception, a 

 well-known horizon — the strata of the scissi hemera — from the Dorset coast to 

 Northamptonshire. The exception is Tm. Hollandae, the date of which is Mur- 

 chisonse hemera. 



At Burton Bradstock and Chideock Quarry Hill, on the Dorset coast, species 

 of Tmetoceras are found in the stratum capping the " Sands " — the bed with 

 Liocerata (see p. xxxv). 



In Gloucestershire, in the Cotteswolds around Stroud, at Robinswood Hill 

 (Mr. L. Richardson), at Andoversford, species of the genus have been found in the 

 " Sandy Ferruginous Beds." 



The " Northampton Sands " of Northamptonshire have yielded specimens 

 which I have verified: they are doubtless the Am. niortensis mentioned by Sharpe. 



The Paving Bed of Bradford Abbas (date Murchisonae »/) has yielded two 

 species : one, Tin. Hollandae, is indigenous ; the other, aff. Tin. circulare, is derived 

 presumably — the matrix in the whorls differs from that enclosing the specimen. 



There are specimens in my cabinet from Italy and Normandy, and the genus 

 has been found in South America (Gottsche). 



1. Tmetoceras circulare, S. linrlr, nun. Plate XLVIII, figs. 1 — 3. 



1892. Tmetoceras scissum, This Mouogr., PL xlviii, figs. 1 — 3 ; p. 273 (pars). 



Description. — Substeno- (on the line, 50 per cent.) subpachygyral ; perlatum- 

 bilicate ; costate ; periphery sulcate, the sulcus interrupting the costse, of which 

 each one terminates in a tubercule on the edge of the sulcus. 



Distinction. — Very like A. scissus, Benecke, in proportions and appearance, but 

 the whorl is rounder, and more inflated. 



2. Tmetoceras scissum (Benecke). Plate XLVIII, figs. 4— 7. 



1892. Tmetoceras scissum, This Mouogr., PI. xlviii, figs. 4 — 7; p. 273 (pars). 



