42 



"would lead to important and valuable conclusions. The two principal 

 excavations on the hill are kept open for the purpose of supplying the 

 surveyor of roads with materials. The Marlstone is sometimes used in the 

 parish roads to form a foundation, which, with a facing of Bristol 

 stone (Carboniferous Limestone), is considered to be an economical and 

 inexpensive method of road making. 



SoTTTH QuAEET. In the south, or larger quarry, the beds lie horizon- 

 tally or nearly so, and exhibit but slight traces of disturbance. The 

 following section will exemplify the Communis beds, 'No. 1 : 

 § 1.] COMMUNIS ZONE AT CHURCHDOWN.— SOUTH QUAREY. [Dip N. 8°. 



The last layer, No. 6, of the section (blue and yellow clay), is frequently 

 chequered with an orange coloured matter, or stain of peroxide of iron, 

 combined with silicate of alumina. It contains numerous Ammonites, 

 either much compressed or else in casts, that are beautifully sharp and true. 

 These Ammonites appear to be slightly bent, as if pressure had been applied 

 obliquely and irregularly. This is the bottom bed of the Communis series, 

 and rests upon a bed of light coloured friable Marlstone, containing a course 

 of large iS'odules, which I shall designate hereafter as the Nodular Bed. 

 The next member, ascending, is the Leptoena Bed, {la Couche A Leptoena, 

 Deslongchamps) made so well known at Ibninster by Mr. Mooee, and at 

 May, in the Calvados, by M.M. Dbslongchasips* Here a new order of 

 zoological facts presents itself. A new fauna occurs. Nature, strange to 

 say, has here resumed an old world type, has taken a form from those old 



♦ The discovery of the Leptoena Bed in the vicinity of Caen, presents so good an instance 

 of what Dr. Whewell (Philos. Inductive Sciences, vol. ii, p. 30) terms "The Colligation of 

 Facts," that I may be pardoned for citing M.M. Deslongchamps' account. They say, " Les 

 nombreuses analogies existant entre les couches d'Angleterre et ceUes de Normandie, qui 

 font partie toutes deux d'un meme bassin, le bassin anglo-parisicn, nous faisait esperer de 

 rencontrer dans les environs de Caen la couche qui avait fourni ces coquiUes si remarquables." 

 — Bulletin de la Soc. Linn, de Normandie, vol iii. Acting on this impression, M. Perrier 

 hit upon the bed at May, whence the Deslongchamps traced it through Evrecy, Landes, 

 and Curcy. 



