Scientific Intelligence—Botany. 373 
places, size, and forms, whether any relation can be established 
between their variations and other phenomena.—(From the Right 
Hon. the Earl of Harrowby’s Address to the British Association 
at Liverpool.) 
‘BOTANY. 
14. The Age of the Cypress Forests.—The plain on which the 
city of New Orleans is built rises only nine feet above the sea, and 
excavations are often made far below the Gulf of Mexico. In these 
sections several successive growths of cypress timber have been 
brought to light. In digging the foundation for the gas-works, the 
Irish spadesmen, finding they had cut through timber instead of 
soil, gave up the work, and were succeeded by a corps of Kentucky 
axemen, who hewed their way downwards through four successive 
growths of timber, the lowest so old that it cut like cheese. Abra- 
sions of the river banks show similar growths of sunken timber, 
while stately live oaks, flourishing on the banks directly above them, 
are living witnesses that the soil has not changed its level for ages. 
Messrs Dickeson and Brown have traced no less than ten distinct 
cypress forests at different levels below the present surface, in parts 
of Louisiana where the range between high and low water is much 
greater than it is at New Orleans. These groups of trees (the live 
oaks on the banks and the successive cypress beds beneath) are 
arranged vertically above each other, and are seen to great advan- 
tage in many places in the vicinity of New Orleans. Dr Bennet 
Dowler has made an ingenious calculation of the last emergence of 
the site of that city, in which these cypress forests play an import- 
ant part. He divides the history of this event into three eras—l. 
The era of colossal grasses, trembling prairies, &c. as seen in the 
lagoons, lakes, and sea coast; 2. The era of the cypress basins; 3. 
The era of the present live oak platform. Existing types, from the 
Belize to the highlands, show that these belts were successively de- 
veloped from the water in the order we have named, the grass pre- 
ceding the cypress, and the cypress being succeeded by the live oak. 
Supposing an elevation of five inches in a century (which i is about the 
rate recorded for the accumulation of detrital deposits in the valley 
of the Nile during seventeen centuries by the Nilometer mentioned 
by Strabo), we shall have 1500 years for the era of aquatic plants 
until the appearance of the first cypress forest, or, in other words, 
the elevation of the grass zone to the condition of a cypress basin. 
Cypress trees of ten feet in diameter are not uncommon in the 
swamps of Louisiana, and one of that size was found in the lowest 
bed of the excavation at the gas-works in. New Orleans. Taking 
ten feet to represent the size of one generation of trees, we shall 
have a period of 5700 years as the age of the oldest trees now 
growing in the basin, Messrs Dickeson and Brown, in examining 
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