51 Contact between Archaean and Olenellus Cambrian Sandstone on south side of the road leading past the south end of Sliffs Pond, and about 100 yds east of the fork of the road. Strike Magnetic N 38 E dip 33 W. Sandstone at the contact. The main- ly calcareous shale further west, and still farther west are limestone beds. Fossils. Olenellus Thompsoni. It is evident that unless some un- expected trends take place, the con- tact line between the Archaean and the Cambrian must run about as indicated by the red pencil mark from locality 50 to locality 51. At any rate it can hardly run very far up the hill side judging from the strikes at 50 and 51. Since this is hardly likely to be debatable ground and since it has no doubt been mapped by Mr. Dall, I did not trouble to examine it. 103