diff --git a/src/proto_alpha/lib_protocol/sc_rollup_inbox_repr.ml b/src/proto_alpha/lib_protocol/sc_rollup_inbox_repr.ml
index b34df886f28708d56ef311183546b378c777ed30..84f1461cd79b93b2afe272da162551eb42c96af0 100644
--- a/src/proto_alpha/lib_protocol/sc_rollup_inbox_repr.ml
+++ b/src/proto_alpha/lib_protocol/sc_rollup_inbox_repr.ml
@@ -135,19 +135,7 @@ let equal_history_proof = Skip_list.equal Hash.equal Hash.equal
 let history_proof_encoding : history_proof Data_encoding.t =
   Skip_list.encoding Hash.encoding Hash.encoding
 
-let pp_history_proof fmt cell =
-  Format.fprintf
-    fmt
-    {|
-       content = %a
-       index = %d
-       back_pointers = %a
-    |}
-    Hash.pp
-    (Skip_list.content cell)
-    (Skip_list.index cell)
-    (Format.pp_print_list Hash.pp)
-    (Skip_list.back_pointers cell)
+let pp_history_proof = Skip_list.pp ~pp_content:Hash.pp ~pp_ptr:Hash.pp
 
 module V1 = struct
   (*
diff --git a/src/proto_alpha/lib_protocol/skip_list_repr.ml b/src/proto_alpha/lib_protocol/skip_list_repr.ml
index cc65a1d5e6e674a7475343a5238d8f779e4ab340..fc7c0077bd9cf96102e509dc5394061ed55ba9c4 100644
--- a/src/proto_alpha/lib_protocol/skip_list_repr.ml
+++ b/src/proto_alpha/lib_protocol/skip_list_repr.ml
@@ -26,6 +26,13 @@
 module type S = sig
   type ('content, 'ptr) cell
 
+  val pp :
+    pp_content:(Format.formatter -> 'content -> unit) ->
+    pp_ptr:(Format.formatter -> 'ptr -> unit) ->
+    Format.formatter ->
+    ('content, 'ptr) cell ->
+    unit
+
   val equal :
     ('content -> 'content -> bool) ->
     ('ptr -> 'ptr -> bool) ->
@@ -136,6 +143,20 @@ end) : S = struct
       []
     |> List.rev
 
+  let pp ~pp_content ~pp_ptr fmt {content; back_pointers; index} =
+    Format.fprintf
+      fmt
+      {|
+       content = %a
+       index = %d
+       back_pointers = %a
+    |}
+      pp_content
+      content
+      index
+      (Format.pp_print_list pp_ptr)
+      (back_pointers_to_list back_pointers)
+
   let encoding ptr_encoding content_encoding =
     let of_list =
       FallbackArray.of_list ~fallback:None ~proj:(fun c -> Some c)
diff --git a/src/proto_alpha/lib_protocol/skip_list_repr.mli b/src/proto_alpha/lib_protocol/skip_list_repr.mli
index 843003e18a151fd318ad5b23e4ad2bfcbe10ac07..74d18e7dff3ab467b421bf26ba01309376446708 100644
--- a/src/proto_alpha/lib_protocol/skip_list_repr.mli
+++ b/src/proto_alpha/lib_protocol/skip_list_repr.mli
@@ -51,6 +51,13 @@ module type S = sig
      pointers of type ['ptr]. *)
   type ('content, 'ptr) cell
 
+  val pp :
+    pp_content:(Format.formatter -> 'content -> unit) ->
+    pp_ptr:(Format.formatter -> 'ptr -> unit) ->
+    Format.formatter ->
+    ('content, 'ptr) cell ->
+    unit
+
   val equal :
     ('content -> 'content -> bool) ->
     ('ptr -> 'ptr -> bool) ->
@@ -82,7 +89,7 @@ module type S = sig
   val genesis : 'content -> ('content, 'ptr) cell
 
   (** [next ~prev_cell ~prev_cell_ptr content] creates a new cell
-     that carries some [content], that follows [prev_cell]. *)
+      that carries some [content], that follows [prev_cell]. *)
   val next :
     prev_cell:('content, 'ptr) cell ->
     prev_cell_ptr:'ptr ->