288 JURASSIC. 



RhynchoncUa cynoccphala occurs in the sands. The yellowish-brown 

 cliffs present a picturesque appearance, the many bands of sandy 

 limestone standing out in relief from the softer sands, which more 

 readily yield to the destructive influence of the weather. Here and 

 there a smooth face of cliff may tell of recent slips, the tumbled 

 masses of which are soon removed by the sea. A slight inward dip 

 helps to keep the cliffs perpendicular. 



The basement-beds of the Inferior Oohte, which occur on top of the Sands, and 

 which were grouped by Dr. Wright as the ' Cephalopoda-bed,' were regarded by 

 Prof. Buckman as palceontologically equivalent to the Gryphite-grit near the top 

 of the Inferior Oolite at Leckhampton ; while the Dorset Sands (in his opinion) in 

 part represent the Lower Freestones of Gloucestershire.^ It may be observed that 

 strictly speaking the whole of the Inferior Oolite near Bridport is a ' Cephalopoda- 

 bed,' and as this is now known to include the zones o{ A. Farkinsotii, A. Hum- 

 phriesiauus, and A. Miirchisona, the Sands below unquestionably represent the 

 Sands at the base of the Inferior Oolite in the Cotteswold Hills. 



The Sands are well exposed in the deep lanes near Beaminster, 

 in the lanes and railway-cuttings near Crewkerne and Yeovil, 

 and at Babylon Hill, between Pen Mill and Bradford Abbas. These 

 have been spoken of as the Yeovil Sands by Mr. Hudleston, and 

 their thickness is about 150 feet. Occasional shelly limestones are 

 met with in the sands at Yeovil Junction and Babylon Hill, and 

 these develope into the celebrated building-stone at Ham Hill, 

 near Martock. Here the section is as follows:- — 



ft. in. 



Ochre beds, yellow sands and sandstone 30 o 



Yellow beds, closely-bedded stone 50 o 



Grey bed, stone S 2 



Bottom bed, hard nodular bed (base of quarry) I 4 



Yellow " Brim Sands," with concretionary beds of sandstone 80 o 



The yellow and grey beds are worked. The stone is almost 

 entirely made up of comminuted shells, but specimens of Ptctcn 

 and Rhynchonella cynoccphala are to be recognized occasionally. 

 Mr. Hudleston recently observed one of these shelly beds in the 

 Sands in a quarry at Stoford, near Yeovil Junction. It was 

 probably about 30ft. or 40ft. below the base of the Inferior Oolite 

 Limestone, and was rich in fossils, including Ammonites Moorei, 

 A. radians, Trigonia angulaia, and Tancredia? 



The Sands cap the summit of Glastonbury Tor (Fig. 39, p. 250) 

 and Brent Knoll, south of the Mendips, where their maximum 

 thickness is about 160 feet. North of the Mendips the thickness 

 is very variable, and the Sands disappear entirely in places. At 

 Bath their thickness is about 40 feet ; they have been well exposed 

 in the tunnel under Combe Down, and in cuttings near Midford. 



In Gloucestershire the Sands and Cephalopoda-bed (the Ammo- 

 nite and Belemnite Bed of the Rev. P. B. Brodie, the Ammonite 

 Sands of Prof. Hull, and Cotteswold Sands of Mr. E. Witchell) are 

 persistent, and have a thickness of from 30 to 150 feet. The 



* Q.J. xxxiii. r, xxxv. 737. 



2 C. Moore, Proc. Somerset Arch. Soc. xiii. ; see also Buckman, Ibid. vol. xx. 



^ P. Geol. Assoc, ix. 190. 



