2. • It was proposed by a geologist Dr lyell in 1830-33.
• According to this theory “present continents are
fixed portions of earth crust and occupy the
same relative position in past as they do today”
• He proposed that continents have changed in
detail under the various physical forces. Lands
emerges, mountains ranges worn out and thrown
away, oceans invaded some lands etc.
3. Drawback
• This theory did not explained the presence of
same animal groups in remote continents,
separated by vast oceans.
