181 NATURAL HISTORY. 



extremity of the Worli Ridge, and again was emptied, or nearly so, 

 as the tide flowed out, much in the same way as we see to-day the 

 low-lying ground about the muddy creeks of Salsette. The entrance 

 being so small and the space beyond so great, it is clear the tide can 

 never have flowed with any great force over the slowly shelving 

 ground inside. Hence it is natural that whatever creatures died in 

 these sheltered shallows, or were drifted into them from the sea 

 outside, would there soon be silted up and preserved in the soft 

 in-washed mud. Hence it is that you will find every spadeful of the 

 soil of the Byculla Flats literally full of the remains of countless 

 sea creatures in a semi-fossilized condition, and for the most part 

 in a wonderfully well-preserved state. 



This lump of earth, marked No. 1, is an instance. It was found 

 near the race-course on the top of a bank of earth made of the soil 

 excavated on the spot.. Of course the texture of the shells in many 

 instances is greatly altered, or even completely changed, generally 

 owing to the highly aluminous nature of the clay or siliceous condi- 

 tion of the water in which they were deposited. But this only show r s 

 how long such specimens must have been lying undisturbed exposed 

 to these influences ; and the fact that they have so well retained their 

 original forms shows how very gradual was the operation of the influ- 

 ences to which they were subjected. The group of fragments of 

 tubular shells, marked No. 2, illustrates this alteration in texture while 

 the original form is preserved. A yet more curious illustration is 

 afforded in every handful of earth about the brick-fields on the west of 

 the Byculla Flats. The soil here is somewhat laminate, very friable, 

 and full of small crystals, apparently of gypsum. And its effect on 

 the shells buried in it seems to have been in some instances to crys- 

 tallize them, and in others to turn them a dark brown or black 

 colour. In either condition they still retain their original form, but 

 are so brittle, or rather rotten, that the slightest touch reduces them 

 to powder, and I have found it impossible to bring any here in 

 a recognisable shape. 



The alteration in texture, considered in connection with the nature 

 of the surrounding soil and general character of the locality, would be 

 of special interest to the geologist. But the shells themselves, 

 whether their texture is altered or not, present several points of 

 interest to the zoologist which I venture to think would amply repay 

 their careful study by a skilled conchologist. I have therefore pre- 

 sumed to invite to them the attention of the members of the Bombay 



