1. During each planetary round, every kingdom or life-wave goes through seven stages of development on each globe. In the human kingdom, these stages are called root-races or humanities. The root-races overlap: a new race begins in the middle of the previous one. Each root-race contains the same egos that were evolving in the preceding root-race.
2. The current planetary manvantara of the earth-chain began approximately 2 billion years ago. Sedimentation on this globe in the fourth round began approximately 320 million years ago, though this does not fully include the evolution of the three elemental kingdoms. The first root-race did not begin until after the awakening from their obscuration of the mineral, vegetable, and animal kingdoms (except the higher mammals which in the fourth round followed man).
3. A maha-yuga lasts 4,320,000 years (one-thousandth of a day of Brahma), and consists of four smaller yugas: the satya- or krita-yuga lasts 1,728,000 years, the treta-yuga 1,296,000 years, the dvapara-yuga 864,000 years, and the kali-yuga 432,000 years.
4. As a general rule, a root-race lasts for two maha-yugas (8.64 million years). During the first maha-yuga, the race reaches its zenith. A racial cataclysm then ensues, and during the second maha-yuga the old race slowly dies out while a new one emerges and pursues its evolution towards maturity. The fifth race in particular will last for two maha-yugas. The fourth race lasted somewhat longer, the sixth and seventh races will be slightly shorter, and the first three races were considerably longer.
 General references: The Secret Doctrine [SD], 2:709-15; Studies in Occult Philosophy [SOP], 164-6; Dialogues of G. de Purucker [Dia], 2:198-9, 3:181-2; H.P. Blavatsky: The Mystery [HPBM], 165-6; The Esoteric Tradition [ET], 323-7.
 Occult Glossary [OG] (2nd ed.), 142-3; Fundamentals of the Esoteric Philosophy [FEP] (2nd ed.), 293-4. Note that there are really 10 or 12 root-races (Dia 3:203; Esoteric Teachings, 4:84).
 Fountain-Source of Occultism [FSO], 166; SD 2:146fn.
 SD 2:68; Isis Unveiled, 1:32.
 SD 2:68, 314, 395, 710, 715fn; ET 323-5; SOP 360; FSO 161; Dia 3:181-2.
The following is a rough guide to the geological periods as used by HPB (SD 2:710, 314fn, 395): the Primordial Age (comprising the Laurentian, Cambrian, & Silurian) began 320 million years ago; the Primary Age (comprising the Devonian, Carboniferous, & Permian) began about 148 million years ago; the Secondary Age (comprising the Triassic, Jurassic, & Cretaceous) began about 44 million years ago; the Tertiary (comprising the Eocene, Miocene, & Pliocene) began about 8 million years ago; and the Quaternary began about 870,000 years ago.
These figures differ from the ‘scientific’ figures derived from radiometric dating – a method that fails to take account of the process of condensation and materialization which predominated during the arc of descent, up to the middle of the fourth round, when the ascending arc of etherealization began (see ET 324-7, 453-4, 760). For further details, see Geochronology: theosophy and science.
 OG 189-90.
 SOP 42-3, 165-6; FSO 165-6.
5. The first root-race probably originated 130 to 150 million years ago in the Silurian or Devonian period, or possibly in the Carboniferous period, of the Paleozoic era, and ended in the Permian period.
6. The second root-race originated in the late Carboniferous or in the Permian, and ended in the late Triassic or early Jurassic of the Mesozoic (Secondary) era (some 25 to 30 million years ago).
7. The third (Lemurian) root-race lived during the Triassic, Jurassic, and Cretaceous of the Mesozoic (the Age of Reptiles). The middle of the third root-race occurred about 18.5 million years ago (near the Jurassic/Cretaceous boundary), when the separation of the sexes and the awakening of mind took place.
8. The fourth (Atlantean) root-race originated in the later Cretaceous (10 to 12 million years ago). It attained its peak in the Eocene of the Tertiary, and was largely destroyed in the Miocene. The midpoint of the fourth round was reached in the middle of the fourth subrace of the fourth root-race, some 4.5 million years ago.
 SD 2:150, 312, 715fn; HPBM 165-6; SOP 165; Dia 2:198-9, 3:181-2. The first race, in the manner in which HPB speaks of it, was so long because it included the slow awakening of the human shishtas (see OG 160-1), before the first race began as a distinct race (SOP 162-3).
 SOP 165; Dia 2:199; HPBM 165-6; ET 325; SD 2:684.
 SD 2:69, 148-9, 250-1, 679, 737; HPBM 166; SOP 164-5; Dia 3:181. But see also: SD 2:204, 713; ET 324; Man in Evolution [MiE], 240; Dia 2:199. HPB says that the actual duration of the first two and a half races is withheld from all but the higher initiates (SD 2:312).
 SOP 164-5; SD 2:717; HPBM 166; ET 1044, 1046; Dia 2:162.
 SOP 20-1, 638-40; ET 1046, Dia 1:88; SD 1:439fn, 2:147fn. The middle of the fourth race is sometimes said to have occured 8 to 9 million years ago (ET 326fn; SOP 20-1, 97, 161, 422; MiE 152) because this is half the period of about 18 million years that has elapsed since the middle of the third root-race.
9. The seeds of the fifth (Aryan or Indo-European) root-race began to emerge 7 or 8 million years ago. The satya-yuga of the fifth race began about 4.5 million years ago, when the fourth race was finishing its kali-yuga. The fifth race became a distinct racial stock about one million years ago in Central Asia. The kali-yuga of the fifth race began in 3102 BC.
10. The subdivisions of a root-race and their approximate durations are as follows:
Root-race 8,640,000 years (2 maha-yugas) Subrace 1 1/4 mill. years Family race 180,000 years National race 25,920 years (one precessional cycle) Tribal race 3600 years Tribal generation 500 years Individual 72 years
Starting from the ‘ideal’ lifetime of a human individual – 72 years – each successive figure is about 7 times the preceding one.
11. The European nations are the fourth national race of the Caucasian family race of the fourth subrace of the fifth root-race. The fourth national race originated about 9000 years ago and has about another 16,000 years to live, before a series of cataclysms cause the submergence of many parts of Europe and usher in the next cycle of civilization.
12. The seeds of the sixth root-race will appear largely in the Americas, and will become fairly numerous towards the end of our kali-yuga. The sixth race will last for about a maha-yuga and a half, or something over 6 million years, and the seventh root-race will be shorter.
NB: For a description of the root-races see: Evolution in the fourth round, ‘Lost pages of evolutionary history’ (MiE 231-46), and ‘Esoteric teachings on the evolution of human and animal beings’ (ET 304-39).
 SOP 638-40.
 SOP 16-25, 638-40; SD 2:147fn, 435.
 SD 1:661-5, 2:435.
 SOP 35-9; FEP 294-5; SD 2:434-5. A ‘national race’ is sometimes called a ‘family race’. ‘Subrace’ can refer to any of the various subdivisions of a root-race. For an explanation of HPB’s statement that we are in the ‘fifth subrace’, see FEP 280-2, 293; SOP 35-9, 484-6. Another interpretation is that it refers to the fifth ‘subrace’ of 210,000 years (SD 2:435) since our fifth humanity became a distinct root-race about one million years ago.
 Which of the seven family races this is can be worked out from the information given at SD 1:439fn and SOP 35-9, bearing in mind that the root-races overlap.
 SD 2:330-1; SOP 35-9, 41, 485-6, 702-3; FSO 163-4; FEP 280/2; OG 143.
 SOP 39, 165-6, 639-40; Dia 2:215-7; FSO 165-6; SD 2:444-6.
by David Pratt. November 1997. Last revised: December 2007.
Rounds and manvantaras: an outline
Geochronology: theosophy and science
Evolution in the fourth round