and Orbitella with fibrous shells. Pentagria origulata appears to occur at about the middle of the reef and then upwards at nearly all levels. Archaeocathus gets larger in the upper part of the reef but is practically absent at 30 feet above the base. The cylindrical stemmed forms are also better developed and larger in the upper part of the reef. It is now evident that we are not going to get a huge fauna and nothing in the way of interesting trilobites. If so we have had too small imperfect leads of Orbenelles. (The next day we got about six more but no good large leads.) One is struck with the thick and calcareous nature of the shells of most brachiopods here in the Lower Cambrian. It is only the small Paterina labadoica and the much larger Paterina that have phosphatic shells. The phosphatic adaptation seems to be a latter phase than the calcareous secretion.