152 



CAPE COD GEOLOGY 



U. S. G. S. Coll. 9,572. Chilmark, Marthas Vineyard, Mass. Collected 

 by A. F. Foerste, Sept., 1889. 



Matrix: Coarse red ferruginous sandstone, with small quartz pebbles. Unidentified 

 pelecypods. 



U. S. G. S. Coll. 9,569. From Indian Hill near the site of an old school- 

 house, Marthas Vineyard, Mass. Collected by J. B. Woodworth, June 18, 1889. 



Matrix: Medium coarse ferruginous sandstone. 



Ostrea sp. (Same as in U. S. G. S. Coll. 1638, p. 2.) 

 Exogyra sp. 

 Gervilliopsis'i 

 Corbula sp. 



U. S. G. S. Coll. 9,571. Lagoon Pond, Marthas Vineyard, Mass. Collected 



by L. F. Ward, Aug. 7, 1889. 



Matrix: Dark red, fine, micaceous ferruginous sandstone, probably an oxidized iron 

 carbonate concretion. 



Ostrea sp. (Same as in U. S. G. S. Coll. 1638.) 

 Pecten cf. P. argillensis Conrad. 

 Paranomia! 



U. S. G. S. Coll. 9,568. A boulder on Gay Head cliffs, Marthas Vineyard, 



Mass. Collected by J. B. Woodworth, June 1889. 



Matrix: Medium coarse, micaceous ferruginous sandstone, with small quartz pebbles. 

 Gervilliopsis? 



Ostrea sp. (Same as in U. S. G. S. Coll. 1638, p. 2.) 

 Exogyra ponderosa Roemer? 

 Pecten cf. P. argillensis Conrad 

 Cardium sp. 



Corbula cf. C. carolinensis Conrad 

 Small unidentified gastropods 



The fossils listed above were all obtained in pieces of ferruginous rock. 

 Though showing a general similarity in lithologic appearance these rocks may 

 nevertheless be divided into two types, which are probably different facies of 

 the same formation. One facies consists of dark red, fine micaceous ferruginous 

 sandstone, probably the oxidized product of concretionary sandy masses of 

 iron carbonate. Some of the specimens have a dark greenish-gray, only partly 

 weathered core; some possess the contraction cavities characteristic of septaria, 

 and many of the cavities are lined with small crystals. The localities of this 

 facies are: 



U. S. G. S. Coll. 9,571. Lagoon Pond 



U. S. G. S. Coll. 788. Lagoon Pond, 2 miles above Vineyard Haven 



U. S. G. S. Coll. 1,638. Oklahoma Cliffs, Lagoon Pond 



