E. M. Kindle — Bottom Control of Marine Faunas. 455 



of the fossil faunal facies as determined by bottom conditions 

 is but little greater than the influence of the winds on land in 

 mixing the products of plant life of swamp, upland and desert 

 habitat. 



The grouping of species on the intertidal zone of the Nova 

 Scotia coast is not less instructive than that of the shallow 

 water zone near shore. The fauna of the intertidal zone 

 illustrates the same class of facts respecting the influence of 

 the character of habitat on variety and number of marine in- 

 vertebrates as the zone immediately below low tide. A com- 

 paratively small number of species live in this zone, but some 

 of these are represented by enormous numbers of individuals 

 where the conditions of life are favorable. Balanus, a genus 

 not included in the lists given because it is a crustacean, is 

 sometimes represented by thousands of individuals to the 

 square yard. Its presence or absence is determined entirely by 

 the physical character of the beach. The great vertical range 

 of the tides on this coast, amounting to 40 feet or more at most 

 points, gives an intertidal zone of far greater width and area 

 than that found on most coasts. In considering the fauna of 

 the intertidal zone station 5 will be omitted because it repre- 

 sents essentially a faunal aggregation due to wave action. The 

 shells collected at this station are from the beach at the head 

 of St. Mary's Bay where Avave action is at times effective in 

 bringing together molluscs derived from various types of 

 habitat. 



The beaches at Digby (fig. IB) and the shore at Bear 

 Island, four miles JSL E. of Digby, furnish representative 

 examples of the fauna of the intertidal zone of the Bay of 

 Fundj. The shore of the island and the eastern part of the 

 beach at Digby is strewn with glacial bowlders of various sizes 

 with gravel, sand and shingle between. Nine species were 

 collected on the Digby beach and four on the Bear Island 

 beach. While all of the latter were found on the Digby beach, 

 it is interesting to note that only two of the 9 species com- 

 prising the Digby and Bear Island beach fauna were found in 

 the black mud fauna of the bay which was dredged only a few 

 hundred yards from the Digby beach. Although only a few 

 species are present in this intertidal fauna at Digby and Bear 

 Island, an enormous number of individuals represent some of 

 these species. The bowlders are often closely covered with 

 small gasteropocls. In many localities there are probably 

 several hundred specimens of Littorina litorea to the square 

 yard. Evidently this rocky beach affords a highly favorable 

 molluscan environment where life is so abundant that every 

 step on the beach destroys scores of shells. 



