this channel is somewhat difficult, on account of the swift current and 

 rough bottom, and can hardly be attempted with safety when the tide 

 is flowing with its full force. The fauna is, however, very remarkable 

 as showing 'the influence of physical conditions on animal life, for 

 here, at the depth of 40 to 60 fathoms, we dredged nearly the same 

 assemblage of animals that are found on the opposite rocky shores, 

 between high and low water mark, together with many of the same 

 forms of sea-weeds. Among the more abundant species were Mytilus 

 edulis, Modiola modiolus, Mya arenaria, Saxicava arctica, Buccinum 

 undulatiim, Ascidia complanata Fab. (A. callosa St.), Cynthia pyri- 

 formis, Boltenia reniformis, various species of Bryozoa and Hydroids, 

 Ophiopholis aculeata, Astenas vulgaris, Cribrella sanguinolenta, Eury- 

 echinits Drobachiensis, Pentacta frondosa, Cancer irroratus, Thelphiisa 

 circinnata (Lumara flava St.), etc. There was, in fact, scarcely any* 

 thing in the dredgings brought up from the deepest parts of this 

 channel that would have indicated a depth of more than one or two 

 fathoms below low water mark, along the shores, and most of the 

 species can readily be obtained at low water of ordinary tides. This 

 is doubtless due to the powerful current which rushes through the 

 channel like a rapid river, and flowing over the rough and irregular 

 bottom, completely mixes up the water from top to bottom, so that 

 there is really no appreciable difference in the temperature or other 

 conditions of the water of the bottom and surface. A third channel, 

 which is narrower and quite shallow, connects the southern end of 

 the harbor with the Bay of Fundy, passing between Campo Bello on the 

 east and Treat's Island and Lubec on the west. This channel is suffi- 

 ciently deep for the Boston steamers and large vessels at high water, 

 but after half-tide is not safe except for small craft, and sometimes, 

 at extremely low tides, it becomes nearly bare. The bottom is mostly 

 muddy and soft. A fourth, narrow, but deep, rocky channel, passing 

 between Treat's Island and the southern end of Moose Island, com- 

 municates with the extensive bodies of water known collectively as 

 Cobscook Bay, but consisting, practically, of several distinct bays, 

 or fiords, which have received local names. The southern branch, 

 known as South Bay, was pretty fully explored with the dredge. 

 These bays receive and discharge great volumes of water at every 

 tide, nearly all of which passes into and through Eastport Harbor, and 

 together with that which supplies St. Andrews Bay, it mostly comes in 

 and goes out through the channel first described, between Campo 

 Bello and Deer Island. As a result of this arrangement, Eastport 

 Harbor is characterized by a powerful and somewhat complicated 

 system of tides, which can- be best understood by examining a chart 

 of the harbor, with the soundings indicated, and comparing the re- 

 spective channels to river valleys, when it will be found that, as a 



