IMPORTANCE OF MINUTE THINGS. 165 



supply argument enough for a lecture on the importance of minute 

 things in this life of ours ; and doubtless heredity has handed down 

 the bad ott'ects of nioditied tissues in past generations of the sick 

 and the sorry to the siilferers and idiots of to-day. But there are 

 many less disagreeable subjects within the range of our text, taking 

 illustrations for both the past and the present from among Common 

 Things. We may group them thus : — Important, though minute, 

 things of life in the Yegetable world : Nullipores, and nullipore- 

 limestone ; Corallines, and coralline shore-sand and raised beaches ; 

 Characea?, and chara-limestone ; Diatomacese, and diatomaceous 

 earths; Equisetums and grasses (canes, wheat, hay, etc.); Puff-ball, 

 Lycopodium, and spore-coal; Lichens on rock, and the formation of 

 soil. In the Animal world : Sponges and spicules, and spicular sand- 

 stones (chert, etc.); Polycystina, and polycystine beds (Barbadoes); 

 Entomostraca (ostracods), marine and freshwater, ostraoodous lime- 

 stones ; Foraminifera, and foraminiferal limestones. 



jSTow I propose to speak of some of these in order. The enormous 

 accumulations of limestone to which the Nullipores give rise are 

 astonishing. Perhaps the best way to realise this is to think of the 

 island of Malta, which is of so much importance to this country. 

 It is made up of five great beds of rock, some hard, and some 

 softer. But the topmost bed, for many square miles, is largely made 

 up of this kind of calcareous seaweed. The common building-stone 

 of Vienna is made up of similar lime-bearing seaweeds in a fossil 

 state. Paris, we may say, — speaking of the stone used for houses, 

 — is built of Foraminifera ; and London is built of mud — loam fit for 

 bricks. Other materials of which London is built, v^esides the brick- 

 earth, consist also of minute particles. The beautiful front of the 

 nqw Army-and-Navy Hotel is built of fine-grained sandstone from 

 Northumberland. St. Paul's, the Monument, Somerset House, and 

 many large old-fashioned houses are built of Portland stone, which 

 is composed to a great extent of particles of oyster-shells stuck 

 together. 



But to go back to the Nulliporcs, the calcareous seaweeds. 

 There is a tiny, jointed, branched, white, skeleton-like seaweed, 

 growing on the rocks of the English coast ; but it occurs in. such, 

 enormous abundance in the "West Indies and elsewhere, that the 

 little joints, parting away from each other, form whole beds of 

 calcareous sand, and when hardened on the sea-beach by spring- 

 water, rain, and sea-spray dissolving the carbonate of lime and 

 mixing it up with the particles, they form limestone. You have 

 heard of the human fossil from Guadaloupe which is in the 

 British Museum, — that is imbedded in this kind of rock. 



The Chara, very well known to Naturalists, is a little freshwater 

 plant, Avith its tissues full of carbonate of lime, and when it dies this 

 mineral matter remains behind. Not many years ago I saw a lake 

 or pond drained in Shropshire, and the mud was quite white, the 

 calcareous atoms becoming bleached in the sun. Such material, got 

 by draining some Forfarshire lakes, has been used in Scotland for 

 manuring fields. 



