Background
Georg Friedrich Jager was born on December 25, 1785, in Stuttgart, Germany. He was the youngest son of Christian Friedrich Jaeger, a court physician, and Luise Friederike Sonntag.
1850
In 1850 Jager received the Knight's Cross of the Order of the Württemberg Crown.
Geschwister-Scholl-Platz, 72074 Tübingen, Germany
Jager studied medicine at Tübingen and received the Doctor of Medicine degree in 1808.
paleontologist physician scientist
Georg Friedrich Jager was born on December 25, 1785, in Stuttgart, Germany. He was the youngest son of Christian Friedrich Jaeger, a court physician, and Luise Friederike Sonntag.
Jager attended the Stuttgart Gymnasium, studied medicine at Tübingen, and received the Doctor of Medicine degree in 1808. He then spent a year traveling, during which he studied osteology and fossil skeletons under Georges Cuvier at Paris.
In Stuttgart Jager established a successful medical practice, becoming a member and eventually senior councillor of the Medicinal Collegium. From 1817 until 1856 he held the post of inspector of the royal natural history-cabinet, and from 1822 until 1842 was also a professor of chemistry and natural history in the Stuttgart Obergymnasium.
In 1822 he discovered in the collections of the Stuttgart Gymnasium a slab of limestone containing a large reptile skeleton, and within this skeleton a much smaller one. Although it was unlike any reptile described by Cuvier, Jager recognized its similarity to the fossil remains recently described in England and named Ichthyosaurus. His monograph contains careful observations (considering the unexposed condition of the fossil) and judicious inferences. He pointed out that the structure of the limbs is more like the paddles of a porpoise than the feet of either salamanders or crocodiles, the animals between which it had been placed in classifications. In 1842 and 1852 he suggested that the small skeleton might be that of a fetus, and that ichthyosaurs may have given birth to living young.
Jager’s monograph on fossil plants of the Triassic sandstones near Stuttgart (1827) was followed in 1828 by a more extensive study of fossil reptiles, which contains the earliest descriptions of labyrinthodont amphibians and of the crocodile-like phytosaurs of the Triassic. He then turned his attention to the fossil mammals from fissures in the Swabian Alb, in Germany, and in 1835 and 1839 provided the first detailed account of this material. This account was important for Jager’s recognition of considerable differences between the faunas of different localities.
In the absence of any super-positional relationships between fissures, he failed to grasp the implication of these differences for the relative ages of the faunas; instead, he sought to explain them by varying circumstances of deposition and accumulation of the bones. Although he attempted to fit them into the Cuvierian concept of an ancient fauna (that of the Paris gypsum) and a more recent assemblage of still-living animals mixed with not long-extinct species such as were found in caves and river alluvium, he repeatedly expressed doubts about this interpretation, and arranged the various faunas in their proper time sequence. He also described the tusks of mammoths and associated fossils found near Stuttgart in 1700 and 1816. In addition to these monographs, Jager wrote many shorter articles on various vertebrate fossils.
Jager was a member of thirty-five academies and learned societies.
Physical Characteristics: Jager was a large man and had robust health.
Jager married twice and had thirteen children.