CHAPTER XII. 



THE CAMBRIAN STRATA OF THE ATTLEBORO DISTRICT. 



Among the most interesting results of the examination of the geology 

 of the ISTarragansett Basin has been the discorery of a number of small 

 Olenellus Cambrian exposures. The first of these, locality 1, directly east 

 of Hoppin Hill (PL XXVI), and a mile southwest of North Attleboro, was 

 discovered by Prof N. S. Shaler long before the United States Geological 

 Survey began its work here, but the horizon to which the fossils from this 

 locality belonged was not determined untl the publication of Bulletin No. 

 30 of the United States Greological Survey, by Mr. C, D. Walcott, in 1886, 

 made more widely known the Olenellus Cambrian fauna of this country. 



At locality 1 were found Hyolithes princepsf and Hyolithellus micans? 

 in considerable abundance; a small form of Stenotheca rugosa was fairly 

 common, and a species described later as Salterelh mrvata was also numer- 

 ous. The operculum of Hyolithellus has so far not been found, but the 

 general Cambrian facies of the fauna at locality 1 was readily recognized 

 as early as 1887. In the fall of that year the writer was sent into the field 

 to collect fossils, and the result was the discovery of locality 2, a third of a 

 mile north of locality 1 , which has furnished almost all of the fossils described 

 from the Olendlus Cambrian of Massachusetts, and of locality 3, a mile 

 directly west of locality 2, in the open fields west of a, little stream, and at 

 the northern end of a long farm lane. The number of species found at 

 locality 3 was small, but it added to our information regarding the areal 

 distribution of the Olenellus Cambrian in this part of the field. 



The results of these investigations were published as an appendix to a 

 preliminary report on the geology of the Cambrian in Bristol County, 

 Massachusetts, in 18883 In the determination of species, the^ figures of 

 Bulletin No. 30 (United States Greological Survey) were followed very 

 closely. When widely different forms were figured under the same species, 

 the description was followed as well as possible. The collections the 

 writer was able to examine at that time afforded but little assistance in 



ipreHminary description of North Attleboro fossils, by N. S. Shaler and August F, Foerste: 

 BxxlL Mus. Comp. Zlool. Harvard Coll., Geo! Series, Vol. 11, pp. 27-41, pis. 1-2, Oct., 1888. 

 S86 



