8 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, 1890. 



brought the perfect basaltic columns that were used throughout this 

 region by the wealthier builders of the 15th and 10th centuries. 



I have not been at Dharavi itself, so I cannot speak of the quarry. 

 But the stones can be seen any day at Kalyan on the G. I. P., 

 especially in the revetment of what is called the Shenalla tank, sup- 

 posed to have been built in 1505. Here they are used as bonds, and 

 are quite as perfect in shape as any at the Giant's Causeway, or on 

 the Rhine, though not of any great size. 



Between the Observatory and Kamballa Hill, this same meridian 

 passes through the northernmost point of what was once " Old 

 Woman's Island," now a part of Kolaba. Continue it to the south- 

 ward from the Observatory and it leads you close to the southernmost 

 point of the Prongs, across the harbour's mouth to the outer edge 

 of the Thall Reefs, and right through the middle of Kennery Island, 

 where are some of the finest masses of basalt in the Lower Konkan. 



From this on southward the meridian lies near the outer edge of 

 the " Kennery Flats" and Alibag Reefs, preserving for a distance of 

 about 14 statute miles (N. and S. of Kennery) an almost uniform 

 depth of 17 feet of water. 



Due west of Alibag the edge of this basaltic sea-floor bends to the 

 south, south-east, through the Chaul Kadu Beacon, which may be 

 said to mark the southern end of the great Bombay sea-wall. 



Malabar Hill, standing well to the west of the Observator}^, marks 

 a projecting point or bastion of the main rampart, which throughout 

 its length points to the poles a goad deal more accurately than the 

 needle can be always trusted to do. 



Lay aside the chart, take a map, and you will find that the hills 

 of Salsette and Trombay Islands and the Kankeshwar and Parsik 

 hills on the main land, are similarly " polarized." But when you 

 come to the next range eastward, that of Matheran, this arrange- 

 ment is only visible in single hills, and not in the outline of the 

 whole group ; and the same is the case with the Sagargarh and Funnel 

 Hill Ranges and those of Mauikgarh and Mira Dongar in Pen. 



East of these, again, comes in one of the most curious features of 

 the region. AVc commonly talk of these ranges as " spurs of the 

 ghats," and so perhaps they originally were. But now the " great 

 break off," so graphically described by Mr. Hart, has separated them 



