Cretaceous period

n. geologic timescale from 135 million to 63 million years ago; end of the age of reptiles; appearance of modern insects and flowering plants

The Cretaceous Period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i.e. from 145.5 ± 4.0 million years ago (Ma)) to the beginning of the Paleocene epoch of the Tertiary Period (about 65.5 ± 0.3 Ma). The youngest and longest geological period of the Mesozoic, the Cretaceous constitutes about 80 million years. The end of the Cretaceous defines the boundary between the Mesozoic and Cenozoic eras.
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Noun
1. from 135 million to 63 million years ago; end of the age of reptiles; appearance of modern insects and flowering plants
(synonym) Cretaceous
(hypernym) period, geological period
(part-holonym) Mesozoic, Mesozoic era, Age of Reptiles

144-65 Million Years Ago
The last period of the Mesozoic era may have seen more dinosaurs then ever before. The horned dinosaurs appeared, like the Triceratops and Centrosaurus. The armoured Anklyosaurus, duckbilled Parasaurolophus, and large carnivore Tyrannosaurus were a few of the quickly evolving dinosaurs. Birds became increasingly numerous & flowering plants were emerging. By the end of the Cretaceous period, all large and small ruling reptiles, except the crocodile went extinct.
Tyrannosaurus (rex) 
Corythosaurus (casuarius) 
Anatosaurus(anectens)
Parasaurolophus(walkeri) 
Carnotaurus(sastrei) 
Gallimimus(bullatus) 
Triceratops(prorsus) 
Tarbosaurus(baatar) 
see list of time periods

Geological Eras When H. P. Blavatsky was writing about the age of the earth in The Secret Doctrine she compared the teachings of the scientists of that time and found nothing but confusion and uncertainty as to geological figures. However, Professor Lefevre in his Philosophy adopted an original method of interpreting the data available. Instead of trying to reach exact figures in regard to the length of the entire fossil-bearing period of sedimentation from the Laurentian period to the present day, or of its subdivisions, he worked out the relative durations of the sedimentary deposits. With this for a background the actual duration of the eras and periods could easily be calculated when reliable evidence was found. Lefevre's studies were based on the erosion of rocks and the deposition of sediments, and his conclusions have stood with little modification till now. H. P. Blavatsky noticed that his estimates of the relative duration of the geological ages agreed fairly well with the 'esoteric' information in her possession, and so by adapting her knowledge of the real figures to Lefevre's proportional scale she constructed a time table which, she says, approximates the truth "in almost every particular." Her total of "320,000,000 years of sedimentation" is much less than that of modern geologists, even though she includes the Laurentian period in her table, which they omit. Her "Esoteric" table (Sd 2:710) is as follows:
to be continue "Geological Eras2 "