138 THE ZOOLOGIST. 



came anywhere near doing so. There is a prevalent opinion 

 locally that the tides of the spring season are not on the average 

 so high as at other seasons of the year. And they are generally 

 spoken of by the country folk as " bird tides "—the name 

 assuming by implication that the tides are providentially arranged 

 so as to suit the exigencies of the birds sitting on the salt 

 marshes. As will be seen a little later from my notes, the birds 

 sometimes presume too much upon the clemency of the tides 

 towards their nesting operations. 



The salt marsh in question might be described as an isosceles 

 triangle in shape, with its base abutting on the upland, and its 

 apex dividing two tidal creeks. The highest ground was on the 

 central and most seaward portion of the triangle. There was a 

 gradual sloping away at each side and at the base near the 

 upland. These lower parts were several times submerged by 

 the spring tides during the three months. But the central 

 tableland — as it might be called — was not. The whole variation 

 beween the highest and lowest levels of the marsh would not 

 exceed two feet. The lower margins were deeply intersected by 

 gutters, wide at their mouth, but diminishing as they wound 

 their way inland, until they vanished altogether before the 

 central part of the marsh was reached. These tortuous creeks 

 cut the margin of the triangle into hummocks, in a way charac- 

 teristic of many salt-marshes, which were covered all over their 

 tops by a thick growth of sea-purslane (Atriplex). The higher 

 ground was level and firm ; but its surface was broken by 

 shallow basins and narrow channels, with flat bottoms and 

 steep edges, at the most nine inches deep, and three-parts filled 

 with water. This water was of course salt water, and there 

 were plenty of Crabs and Shrimps in some of them, proving 

 that the tide sometimes filled them. The central tableland 

 was thus divided into irregularly shaped areas of flat ground 

 overgrown with fine grass and a great profusion of thrift 

 (Armeria maritima) and sea-lavender (Statice). The sea-lavender 

 seemed to me to grow most on a slightly lower level of ground 

 than the thrift. It was chiefly on the thrift -bearing ground 

 that the Terns were nesting ; that is, on the highest ground of 

 the whole area, and, therefore, the ground least likely to be 

 touched by the tide. 



