Head, Nantucket, and their Fossils. 



1. Fine dark drifted sand . .. 3 feet 



2. Yellow sandy drift, ferruginous at the bottom and con- 



taining pebbles i 5 " 



4. Coarse gray stratified sand, with particles of greensand .40 " 



5. Fragment bed [4] 1 " 



6. Upper shell bed [3] 8 inches 



7. Clayey ferruginous sand 4 " 



8. Serpula sand [2] , 1 " 3 " 



9. Lower shell bed [1] 9 " 



10. Red sand, with fragments of blue clay 1 " 



11. White sand of varying quality and size 4 " 



Concealed by turf and beach sand 24 " 



Total .91 feet 



In the excavation made the last summer the thickness of the 

 upper two fossiliferous beds seems to be much the same or even 

 of less thickness, while both the intermediate sand and the lower 

 layers seem to be much thicker than given above. 



A photograph of the section is given on Plate II. As the light 

 late in the afternoon was not strong enough to bring out the 

 contacts, pieces of fossil shell were inserted for guides. At the 

 top of the plate is shown the fine white sand, No. 4 of the 

 section. The ferruginous streaks and the bedding are easily made 

 out. Below this between the two upper pieces of shell is the 

 fragment bed, of lighter color than the one below, due to the mass 

 of shell fragments. Below this and extending to the floor of the 

 first shelf of the excavation is the upper shell bed, No. 6 of the 

 section. The floor of this upper shelf is formed by layer No. 7, a 

 clayey ferruginous sand. The bed can be distinguished in the 

 photograph, especially on the right. It extends downward to a 

 point slightly below the shell fragment in its face. Below this is 

 the Serpula bed, made up of tubes, frequently covered by Bryozoa, 

 and also a few shells. This is the thickest of the fossiliferous 

 beds. Its contact with the lower shell bed may be made out at 

 the right of the excavation, slightly below the handle of the 

 shovel. From this point to nearly the top of the blade of the 

 shovel extends the lower shell bed, the shells in place easily made 

 out in the photograph. From this to the lower shelf on which the 

 shovel rests is layer No. 10 : a reddish sand with pieces of sticky 

 blue clay. This also makes up the floor of the shelf and its 

 contact with the white sand bed below it may be made out in the 

 vertical face nearest the observer. 



