PLEISTOCENE FORMATIONS OF SANKATY HEAD 719 



occur, none showing wear. Pebbles not numerous, commonly 

 rounded, rarely angular; no clay. This is the so-called "oyster 

 bed." 



No. g. — Quartz sand, with ground-up shell material, and often 

 solid masses of Serpula dianthus; fine material, largely fine sand, 

 common among the talus; pebbles, except small ones, not common; 

 no clay or glauconite noticed, but bed hardens on exposure to air. 

 Speciments of Area and Venus, with perfectly preserved surface 

 markings occur, many of the latter with valves together, and liga- 

 ment in place. Solen, Mya, Cummingia, and Ceronia also occur 

 with valves together, the two former noticed in their natural upright 

 position. A number of other species occur, and some fine shell 

 fragments. Some shells are perforated by borings and the serpulae 

 sometimes occur in bunches. This bed is generally referred to as 

 the "serpula bed." 



No. io.- — Coarse quartz sand, much water-worn and rounded, 

 many of the grains coated with iron oxide. Pebbles up to 8 cm com- 

 mon, generally well rounded and largely of quartz; also some fine 

 material of lutaceous character. Shell fragments, and occasionally 

 whole shells, mostly Venus, found throughout. 



No. 11. — Coarse and fine sand, not well assorted. Pebbles 

 angular or sub-angular, 5-6 cm , and even up to 20 cm ; quartz-porphyry 

 quite common. Shells entire and fragmentary, with Ostrea and 

 Venus very abundant, the latter of the var. antiqua. 



No. 12. — Quartz sand of varying grain, full of shell fragments 

 and rounded pebbles, generally small, but some up to i5 cm ; shells 

 generally fragmentary, but many delicate ones are perfect. Large 

 Venus, and well-preserved Buccinum undatum fairly common; shell 

 of Mactra removed, leaving a large bunch of barnacles in the bed 

 in the position in which they had been attached to it ; bed gray, from 

 fragments of Mytilus. 



No. 1 j. — Reddish, highly oxidized, ferruginous sand with rounded 

 and sub-angular pebbles up to 8 cm . This is hardly a distinct bed, 

 but is rather a more pebbly and ferruginous layer in Nos. 12 and 14 

 taken as one bed. 



No. 14. — Like No. 12, but more shelly; resembles an uncemented 

 coquina, full of barnacles, in places almost entirely made up of them 



