239 



composed of several different beds, all containing more or less of 

 the marl; but some of the layers are chiefly made up of siliceous 

 sand, and clay, and ferruginous matter. Over the dark lead-co. 

 loured siliceous clay, a stratum of the sand is seen, often green, 

 though for the most part gray and quartzose. High above this 

 the true marl is seen in many places, and may be known by its 

 white efflorescence. 



The marl taken from the cliffs about two miles northwest of 

 the Telegraph Tavern, exhibits the following, 

 Composition. — In 100 parts: 



Greensand, ... 92-2 

 Clay, - - . - 5-8 



Quartzose sand, - - 2-0 



100 



The proportion of potash, deduced from that of the greensand, 

 is 10-6 per cent. The appearance of this marl is a dull or dirty 

 green, and is little changed by washing. 



Where the cliffs are high, the conglomerate is seen in its natu- 

 ral place, over the top of all. Near the upper surface of the 

 marl bed may be seen large globular masses of indurated and 

 cemented marl, like that found before at Nut Swamp. They Here 

 possess the hardness of a true rock and do not crumble. The 

 freshly fractured surface is often very beautiful, showing the 

 green grains of marl distributed through a cement of argillaceous 

 red oxide of iron. The globular masses are seen in horizontal 

 layers in the marl, and they strew the beach pretty thickly. The 

 blocks of the horizontal iron stone are often several feet in 

 diameter. Sometimes the consolidated ferruginous masses of the 

 cemented sand are the size of a small apartment. 



In several places beneath these cliffs of the Highlands, vast 

 masses of the strata have subsided by the undermining action of 

 the water passing through the lower beds, and they form an 

 under-cliff or landslip with a steep pitch toward the land, bringing 

 down into nearer view the top strata, the upper ferruginous sands 

 of which, owing to the condition of their oxide of iron, are of a 

 most beautiful reddish colour. 



At the shore beneath the Telegraph hill on the ocean side, the 



