Danmarks Handel og Industri

87 In the rest of Denmark the lowest strata — from the latter period of the cretaceous era (the cenozoic age and the mesozoic age) — are formed of ordinary chalk and various kinds of limestone. In many places they will be found so near the surface that it has been possible to quarry and employ the different stones. Chemically regarded the composition of the various lime- stones is almost the same, with about 98 % of calcium carbonate and 1 % of magnesium carbonate in the dry matter, but from a physic-geological point of view they are rather different, in consequence of which they are used for various purposes. The oldest deposit, common chalk, is mainly used in the preparation of cement by mixing it with clay, and burning and levigating it, from which process is produced Portland Cement. The works for the preparation of this article are situated near Aalborg, Nørresundby and Mariager. A very con- siderable production takes place here, and large quantities are exported to foreign countries, in addition to what is used in this country. Common chalk in an unprepared state — natural chalk — is quarried at Stevns Klint in addition to the places already mentioned, and fairly large quantities are exported to foreign countries, especially to Russia and Germany. Common chalk made into whitening — whitened chalk and »water- ground chalk« for colours, putty for the rubber industry etc. — are ex- ported from the aforesaid places. Chalk as manure in farming is quarried in various places besides those mentioned above, and is subjected to a very slight and sometimes to a thorough treatment by drying and levigating it. The following are the most important Danish limestones: Coral limestone: which is exclusively found near Faxe. It is quarried on a large scale and sent to various inland places and exported to foreign countries for use in lime-kilns, sugar factories, celluloid factories, iron works and the like. It mainly consists of more or less transformed coral roots pressed together, and forms a very good and cohesive limestone. Bryozoum Chalk, also called »Limsten« and sometimes chalk stone, is a kind of loose limestone; it is quarried and formed into building stone, espe- cially at Stevns Klint. Pale Chalk is mainly loosely-connected limestone, but in some places in Jutland rather hard deposits occur. Looser deposits are used as manure chalk in the farming industry, the closer deposits for chalk burning. The production of manure chalk from this limestone has been greatly developed during the last decade.