diff --git a/Sed.txt b/Sed.txt
new file mode 100644
index 0000000..9f660bc
--- /dev/null
+++ b/Sed.txt
@@ -0,0 +1,48 @@
+Rocks
+======
+
+Sedimentary layer
+-----------
+
+typy = časticovce(45%), Bio-vce(30%),  Chemo-vce(18%), Vulkano-vce(7%) (order?)
+
+Noise1( 70)= typ
+Noise2(100)= veľkosť častíc, BioTyp
+Noise3(220)= miera spevnenia, kvalita
+
+2D: fast, acceptable imho
+3D: nice
+
+### Časticovce
+
+(Noise3: nespevnené -> spevnené)
+(Noise2: top-hrubé bot-jemné)
+
+štrk gravel(20%) -> zlepenec conglomerate
+piesok sand(10%) -> pieskovec sandstone
+? -> prachovec
+íl clay -> ílovec claystone(40%) -> bridlica slate(50%)
+
+### Bio-vce
+
+Noise2: (top) ropa(8%), Vápenec(60%), iné(20%), uhlie(12%)
+
+iné: fosfáty, silikáty (Noise4?)
+
+Noise3: low -> high
+
+uhlie: Lignit -> č. Uhlie -> Antracit
+iné: Fosfit, Apatit, Rohovec (hornfels)
+ropa: Ropa
+
+# Chemo-vce
+
+- Evapority
+- ?
+
+
+### Nie:
+
+- íl [ílovec + voda]
+Vulkano: (prach?) ->biome only
+ (-> grafit)
diff --git a/a.txt b/a.txt
index e8578f6..df85231 100644
--- a/a.txt
+++ b/a.txt
@@ -15,6 +15,7 @@ Features
 
 * git clone git://repo.or.cz/rocks.git ([show](http://repo.or.cz/rocks.git/))
 * (old) Git clone: [https](https://gitorious.org/mt/rocks.git)
+* Forum [post](https://forum.minetest.net/viewtopic.php?f=9&t=11779)
 
 This mod nor minetest_game/default do not define meaningful biomes. 
 So if you do not want unlimited grassland I suggest installing the 
@@ -49,6 +50,8 @@ Is implemented by modifiing MGv7 biomes to use rocks's sedimentary rocks.
 This means that you need mapgen v7 enabled. I also suggest enabling caves 
 and dungeons, as they are cool. 
 
+Development notes in [Sed.txt](Sed.txt) file!
+
 Soil is normlly 50-70 cm deep in real life, so I made soil (dirt) only 1 
 block thick. Under this thin layer of dirt an sedimentary layer is located. 
 In RL, there is clay and other stuff.