BAR-THEORY OF OCHSENIUS 351 



of its original volume. At tliat time there were 38.45-1.58 or 36.87 

 grams of salts in 0.095 liters of water, which corresponds to 388 

 grams in i liter, or a salinity of 388 permille. The most saline 

 body of water given in the list of salt lakes on p. 154, i. e., Tinetz 

 Lake, has a salinity of only 289 permille, while the next body, 

 the Karabugas Gulf, has a salinity of only 285 permille. It is evi- 

 dent that neither of these waters is saline enough to deposit salts, 

 and this is known to be the case (Andrussow-3). O^^ the other 

 hand, 38.38 grams in 0.190 liter, or a salinity of 202 permille, marks 

 the point at which calcium sulphate will l)e deposited. It is evident 

 that such precipitation can take place in both the above water bod- 

 ies, and that it may indeed take place in all of the nine lakes cited 

 first in the list on page 154. That it does not so take place is in 

 all probability due to the variation in composition of these bodies 

 from normal sea water. Many of these lakes deposit magnesium or 

 other sulphates, and some of them have deposited sodium chloride 

 at a former time of greater salinity. 



Calcium sulphate is a usual accompaniment of salt deposits oc- 

 curring as gypsum or anhydrite, and forming alternating layers 

 with the salt, as in the so-called annual rings {Jahrcsringe) of the 

 Stassfurt and other salts, or as mixtures recognizable only on analy- 

 sis. Only in rare cases is gypsum or anhydrite absent, as in the 

 great deposits of Miocenic age at Wieliczka, where the salt is ab- 

 solutely pure. As seen from the table of Usiglio, pure calcium 

 sulphate is deposited first, and then sodium chloride with small ad- 

 mixtures of calcium and magnesium sulphate and some magnesium 

 chlorides. If now, after a period of salt precipitation, the salinity 

 of the water should become reduced by an unusual influx of sea 

 water, salt deposition will cease, and after a while gypsum or anhy- 

 drite will form to be again succeeded by salt deposits. If, however, 

 the bar remains closed for a period after the precipitation of all 

 the calcium sulphate, only pure salt will be deposited, and this will 

 continue until the mother liquor is nearly depleted of sodium 

 chloride (see the table). After this no more deposition is possible 

 except through renewal of the water across the bar, and so it 

 is evident that the deposition of pure salt is limited in thickness. It 

 is apparent that very thick deposits of pure salt cannot be explained 

 in this manner. 



The influx of much water across the bar may bring with it silt, 

 and this will be deposited first, the succession becoming, from below 

 up, silt, gypsum and salt. With the silt the organisms of the ad- 

 joining sea may enter the bay, but, owing to the rapid increase in 



